diff --git a/app/DataMapper/CompanySettings.php b/app/DataMapper/CompanySettings.php
index a3d272a5c410..8f9dfe2408f4 100644
--- a/app/DataMapper/CompanySettings.php
+++ b/app/DataMapper/CompanySettings.php
@@ -98,11 +98,11 @@ class CompanySettings extends BaseSettings
     public $expense_number_pattern = ''; //@implemented
     public $expense_number_counter = 1; //@implemented
 
-    public $recurring_expense_number_pattern = ''; 
-    public $recurring_expense_number_counter = 1; 
+    public $recurring_expense_number_pattern = '';
+    public $recurring_expense_number_counter = 1;
 
-    public $recurring_quote_number_pattern = ''; 
-    public $recurring_quote_number_counter = 1; 
+    public $recurring_quote_number_pattern = '';
+    public $recurring_quote_number_counter = 1;
 
     public $vendor_number_pattern = ''; //@implemented
     public $vendor_number_counter = 1; //@implemented
@@ -276,6 +276,9 @@ class CompanySettings extends BaseSettings
     public $email_from_name = '';
     public $auto_archive_invoice_cancelled = false;
 
+
+    public $purchase_order_number_counter = 1; //TODO
+
     public static $casts = [
         'page_numbering_alignment'           => 'string',
         'page_numbering'                     => 'bool',
@@ -474,6 +477,7 @@ class CompanySettings extends BaseSettings
         'portal_custom_footer'               => 'string',
         'portal_custom_js'                   => 'string',
         'client_portal_enable_uploads'       => 'bool',
+        'purchase_order_number_counter'      => 'integer',
     ];
 
     public static $free_plan_casts = [
diff --git a/app/Events/PurchaseOrder/PurchaseOrderWasMarkedSent.php b/app/Events/PurchaseOrder/PurchaseOrderWasMarkedSent.php
new file mode 100644
index 000000000000..3b17142b9aab
--- /dev/null
+++ b/app/Events/PurchaseOrder/PurchaseOrderWasMarkedSent.php
@@ -0,0 +1,38 @@
+<?php
+
+
+namespace App\Events\PurchaseOrder;
+
+use App\Models\Company;
+use App\Models\PurchaseOrder;
+use Illuminate\Queue\SerializesModels;
+
+/**
+ * Class PurchaseOrderWasMarkedSent.
+ */
+class PurchaseOrderWasMarkedSent
+{
+    use SerializesModels;
+
+    /**
+     * @var \App\Models\PurchaseOrder
+     */
+    public $purchase_order;
+
+    public $company;
+
+    public $event_vars;
+    /**
+     * Create a new event instance.
+     *
+     * @param PurchaseOrder $purchase_order
+     * @param Company $company
+     * @param array $event_vars
+     */
+    public function __construct(PurchaseOrder $purchase_order, Company $company, array $event_vars)
+    {
+        $this->purchase_order = $purchase_order;
+        $this->company = $company;
+        $this->event_vars = $event_vars;
+    }
+}
diff --git a/app/Factory/PurchaseOrderInvitationFactory.php b/app/Factory/PurchaseOrderInvitationFactory.php
new file mode 100644
index 000000000000..ee3987ea7e39
--- /dev/null
+++ b/app/Factory/PurchaseOrderInvitationFactory.php
@@ -0,0 +1,31 @@
+<?php
+
+
+namespace App\Factory;
+
+use App\Models\PurchaseOrderInvitation;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Support\Str;
+
+class PurchaseOrderInvitationFactory
+{
+    public static function create(int $company_id, int $user_id) :PurchaseOrderInvitation
+    {
+        $ci = new PurchaseOrderInvitation();
+        $ci->company_id = $company_id;
+        $ci->user_id = $user_id;
+        $ci->vendor_contact_id = null;
+        $ci->purchase_order_id = null;
+        $ci->key = Str::random(config('ninja.key_length'));
+        $ci->transaction_reference = null;
+        $ci->message_id = null;
+        $ci->email_error = '';
+        $ci->signature_base64 = '';
+        $ci->signature_date = null;
+        $ci->sent_date = null;
+        $ci->viewed_date = null;
+        $ci->opened_date = null;
+
+        return $ci;
+    }
+}
diff --git a/app/Http/Controllers/ClientPortal/InvitationController.php b/app/Http/Controllers/ClientPortal/InvitationController.php
index 199497ccd7df..48b4a455754b 100644
--- a/app/Http/Controllers/ClientPortal/InvitationController.php
+++ b/app/Http/Controllers/ClientPortal/InvitationController.php
@@ -22,6 +22,7 @@ use App\Models\ClientContact;
 use App\Models\CreditInvitation;
 use App\Models\InvoiceInvitation;
 use App\Models\Payment;
+use App\Models\PurchaseOrderInvitation;
 use App\Models\QuoteInvitation;
 use App\Services\ClientPortal\InstantPayment;
 use App\Utils\CurlUtils;
@@ -41,7 +42,7 @@ class InvitationController extends Controller
     use MakesDates;
 
     public function router(string $entity, string $invitation_key)
-    {   
+    {
         Auth::logout();
 
         return $this->genericRouter($entity, $invitation_key);
@@ -166,7 +167,7 @@ class InvitationController extends Controller
     {
 
         set_time_limit(45);
-        
+
         if(Ninja::isHosted())
             return $this->returnRawPdf($entity, $invitation_key);
 
@@ -202,7 +203,7 @@ class InvitationController extends Controller
         return response()->streamDownload(function () use($file) {
                 echo $file;
         },  $file_name, $headers);
-        
+
     }
 
     public function routerForIframe(string $entity, string $client_hash, string $invitation_key)
@@ -228,14 +229,14 @@ class InvitationController extends Controller
         $invitation = InvoiceInvitation::where('key', $invitation_key)
                                     ->with('contact.client')
                                     ->firstOrFail();
-        
+
         auth()->guard('contact')->loginUsingId($invitation->contact->id, true);
 
         $invoice = $invitation->invoice;
 
         if($invoice->partial > 0)
             $amount = round($invoice->partial, (int)$invoice->client->currency()->precision);
-        else 
+        else
             $amount = round($invoice->balance, (int)$invoice->client->currency()->precision);
 
         $gateways = $invitation->contact->client->service()->getPaymentMethods($amount);
@@ -279,6 +280,10 @@ class InvitationController extends Controller
             $invite = CreditInvitation::withTrashed()->where('key', $invitation_key)->first();
             $invite->contact->send_email = false;
             $invite->contact->save();
+        }elseif($entity == 'purchase_order'){
+            $invite = PurchaseOrderInvitation::withTrashed()->where('key', $invitation_key)->first();
+            $invite->contact->send_email = false;
+            $invite->contact->save();
         }
         else
             return abort(404);
diff --git a/app/Models/PurchaseOrder.php b/app/Models/PurchaseOrder.php
index 4d73c609559d..3a82bb9215f8 100644
--- a/app/Models/PurchaseOrder.php
+++ b/app/Models/PurchaseOrder.php
@@ -12,8 +12,12 @@
 namespace App\Models;
 
 
+use App\Jobs\Entity\CreateEntityPdf;
 use App\Services\PurchaseOrder\PurchaseOrderService;
+use App\Utils\Ninja;
 use Illuminate\Database\Eloquent\SoftDeletes;
+use Illuminate\Support\Carbon;
+use Illuminate\Support\Facades\Storage;
 
 class PurchaseOrder extends BaseModel
 {
@@ -129,11 +133,52 @@ class PurchaseOrder extends BaseModel
     {
         return $this->belongsTo(Client::class)->withTrashed();
     }
+    public function markInvitationsSent()
+    {
+        $this->invitations->each(function ($invitation) {
+            if (! isset($invitation->sent_date)) {
+                $invitation->sent_date = Carbon::now();
+                $invitation->save();
+            }
+        });
+    }
 
+    public function pdf_file_path($invitation = null, string $type = 'path', bool $portal = false)
+    {
+        if (! $invitation) {
+
+            if($this->invitations()->exists())
+                $invitation = $this->invitations()->first();
+            else{
+                $this->service()->createInvitations();
+                $invitation = $this->invitations()->first();
+            }
+
+        }
+
+        if(!$invitation)
+            throw new \Exception('Hard fail, could not create an invitation - is there a valid contact?');
+
+        $file_path = $this->client->credit_filepath($invitation).$this->numberFormatter().'.pdf';
+
+        if(Ninja::isHosted() && $portal && Storage::disk(config('filesystems.default'))->exists($file_path)){
+            return Storage::disk(config('filesystems.default'))->{$type}($file_path);
+        }
+        elseif(Ninja::isHosted() && $portal){
+            $file_path = CreateEntityPdf::dispatchNow($invitation,config('filesystems.default'));
+            return Storage::disk(config('filesystems.default'))->{$type}($file_path);
+        }
+
+        if(Storage::disk('public')->exists($file_path))
+            return Storage::disk('public')->{$type}($file_path);
+
+        $file_path = CreateEntityPdf::dispatchNow($invitation);
+        return Storage::disk('public')->{$type}($file_path);
+    }
 
     public function invitations()
     {
-        return $this->hasMany(CreditInvitation::class);
+        return $this->hasMany(PurchaseOrderInvitation::class);
     }
 
     public function project()
diff --git a/app/Models/PurchaseOrderInvitation.php b/app/Models/PurchaseOrderInvitation.php
new file mode 100644
index 000000000000..c0601653e559
--- /dev/null
+++ b/app/Models/PurchaseOrderInvitation.php
@@ -0,0 +1,81 @@
+<?php
+
+
+namespace App\Models;
+
+
+use App\Utils\Traits\Inviteable;
+use App\Utils\Traits\MakesDates;
+use Carbon\Carbon;
+use Illuminate\Database\Eloquent\SoftDeletes;
+
+class PurchaseOrderInvitation extends BaseModel
+{
+    use MakesDates;
+    use SoftDeletes;
+    use Inviteable;
+
+    protected $fillable = [
+        'id',
+        'vendor_contact_id',
+    ];
+
+    protected $with = [
+        'company',
+        'contact',
+    ];
+    protected $touches = ['purchase_order'];
+
+    public function getEntityType()
+    {
+        return self::class;
+    }
+
+    public function entityType()
+    {
+        return PurchaseOrder::class;
+    }
+
+    /**
+     * @return mixed
+     */
+    public function purchase_order()
+    {
+        return $this->belongsTo(PurchaseOrder::class)->withTrashed();
+    }
+
+    /**
+     * @return mixed
+     */
+    public function contact()
+    {
+        return $this->belongsTo(VendorContact::class, 'vendor_contact_id', 'id')->withTrashed();
+    }
+
+    /**
+     * @return mixed
+     */
+    public function user()
+    {
+        return $this->belongsTo(User::class)->withTrashed();
+    }
+
+
+    public function company()
+    {
+        return $this->belongsTo(Company::class);
+    }
+
+    public function getName()
+    {
+        return $this->key;
+    }
+
+    public function markViewed()
+    {
+        $this->viewed_date = Carbon::now();
+        $this->save();
+    }
+
+
+}
diff --git a/app/Models/VendorContact.php b/app/Models/VendorContact.php
index 5c2e373c8311..2b2fcd3f1252 100644
--- a/app/Models/VendorContact.php
+++ b/app/Models/VendorContact.php
@@ -136,4 +136,8 @@ class VendorContact extends Authenticatable implements HasLocalePreference
             ->withTrashed()
             ->where('id', $this->decodePrimaryKey($value))->firstOrFail();
     }
+    public function purchase_order_invitations(): \Illuminate\Database\Eloquent\Relations\HasMany
+    {
+        return $this->hasMany(PurchaseOrderInvitation::class);
+    }
 }
diff --git a/app/Providers/EventServiceProvider.php b/app/Providers/EventServiceProvider.php
index 57afa3f7e5fe..d2b7e232acfa 100644
--- a/app/Providers/EventServiceProvider.php
+++ b/app/Providers/EventServiceProvider.php
@@ -60,6 +60,7 @@ use App\Events\Payment\PaymentWasRefunded;
 use App\Events\Payment\PaymentWasRestored;
 use App\Events\Payment\PaymentWasUpdated;
 use App\Events\Payment\PaymentWasVoided;
+use App\Events\PurchaseOrder\PurchaseOrderWasMarkedSent;
 use App\Events\Quote\QuoteWasApproved;
 use App\Events\Quote\QuoteWasArchived;
 use App\Events\Quote\QuoteWasCreated;
@@ -558,6 +559,8 @@ class EventServiceProvider extends ServiceProvider
         VendorWasUpdated::class => [
             VendorUpdatedActivity::class,
         ],
+        PurchaseOrderWasMarkedSent::class => [
+        ],
 
     ];
 
diff --git a/app/Repositories/PurchaseOrderRepository.php b/app/Repositories/PurchaseOrderRepository.php
index cf0653c25c8a..d620fdcdd142 100644
--- a/app/Repositories/PurchaseOrderRepository.php
+++ b/app/Repositories/PurchaseOrderRepository.php
@@ -13,6 +13,7 @@ namespace App\Repositories;
 
 
 use App\Models\PurchaseOrder;
+use App\Models\PurchaseOrderInvitation;
 use App\Utils\Traits\MakesHash;
 
 class PurchaseOrderRepository extends BaseRepository
@@ -30,5 +31,9 @@ class PurchaseOrderRepository extends BaseRepository
 
         return $purchase_order;
     }
+    public function getInvitationByKey($key) :?PurchaseOrderInvitation
+    {
+        return PurchaseOrderInvitation::where('key', $key)->first();
+    }
 
 }
diff --git a/app/Services/PurchaseOrder/ApplyNumber.php b/app/Services/PurchaseOrder/ApplyNumber.php
new file mode 100644
index 000000000000..c3fd4d5df078
--- /dev/null
+++ b/app/Services/PurchaseOrder/ApplyNumber.php
@@ -0,0 +1,59 @@
+<?php
+
+
+namespace App\Services\PurchaseOrder;
+
+
+use App\Models\Client;
+use App\Models\Credit;
+use App\Models\PurchaseOrder;
+use App\Services\AbstractService;
+use App\Utils\Traits\GeneratesCounter;
+use Illuminate\Database\QueryException;
+
+class ApplyNumber extends AbstractService
+{
+    use GeneratesCounter;
+
+    private Client $client;
+
+    private PurchaseOrder $purchase_order;
+
+    private bool $completed = true;
+
+    public function __construct(Client $client, PurchaseOrder $purchase_order)
+    {
+        $this->client = $client;
+
+        $this->purchase_order = $purchase_order;
+    }
+
+    public function run()
+    {
+        if ($this->purchase_order->number != '') {
+            return $this->purchase_order;
+        }
+
+        $this->trySaving();
+
+        return $this->purchase_order;
+    }
+    private function trySaving()
+    {
+        $x=1;
+        do{
+            try{
+                $this->purchase_order->number = $this->getNextPurchaseOrderNumber($this->client, $this->purchase_order);
+                $this->purchase_order->saveQuietly();
+                $this->completed = false;
+            }
+            catch(QueryException $e){
+                $x++;
+                if($x>10)
+                    $this->completed = false;
+            }
+        }
+        while($this->completed);
+
+    }
+}
diff --git a/app/Services/PurchaseOrder/CreateInvitations.php b/app/Services/PurchaseOrder/CreateInvitations.php
new file mode 100644
index 000000000000..4ae8f85323e6
--- /dev/null
+++ b/app/Services/PurchaseOrder/CreateInvitations.php
@@ -0,0 +1,91 @@
+<?php
+
+
+namespace App\Services\PurchaseOrder;
+
+
+use App\Factory\PurchaseOrderInvitationFactory;
+use App\Models\PurchaseOrder;
+use App\Models\PurchaseOrderInvitation;
+use App\Services\AbstractService;
+use App\Utils\Traits\MakesHash;
+use Illuminate\Support\Str;
+
+class CreateInvitations extends AbstractService
+{
+    use MakesHash;
+
+    public PurchaseOrder $purchase_order;
+
+    public function __construct(PurchaseOrder $purchase_order)
+    {
+        $this->purchase_order = $purchase_order;
+    }
+    private function createBlankContact()
+    {
+        $new_contact = PurchaseOrderInvitationFactory::create($this->purchase_order->company_id, $this->purchase_order->user_id);
+        $new_contact->client_id = $this->purchase_order->client_id;
+        $new_contact->contact_key = Str::random(40);
+        $new_contact->is_primary = true;
+        $new_contact->save();
+    }
+    public function run()
+    {
+        $contacts = $this->purchase_order->vendor->contacts;
+
+        if($contacts->count() == 0){
+            $this->createBlankContact();
+
+            $this->purchase_order->refresh();
+            $contacts = $this->purchase_order->vendor->contacts;
+        }
+
+        $contacts->each(function ($contact) {
+            $invitation = PurchaseOrderInvitation::whereCompanyId($this->purchase_order->company_id)
+                ->whereClientContactId($contact->id)
+                ->whereCreditId($this->purchase_order->id)
+                ->withTrashed()
+                ->first();
+
+            if (! $invitation) {
+                $ii = PurchaseOrderInvitation::create($this->purchase_order->company_id, $this->purchase_order->user_id);
+                $ii->key = $this->createDbHash($this->purchase_order->company->db);
+                $ii->purchase_order_id = $this->purchase_order->id;
+                $ii->vendor_contact_id = $contact->id;
+                $ii->save();
+            } elseif (! $contact->send_email) {
+                $invitation->delete();
+            }
+        });
+
+        if($this->purchase_order->invitations()->count() == 0) {
+
+            if($contacts->count() == 0){
+                $contact = $this->createBlankContact();
+            }
+            else{
+                $contact = $contacts->first();
+
+                $invitation = PurchaseOrder::where('company_id', $this->purchase_order->company_id)
+                    ->where('vendor_contact_id', $contact->id)
+                    ->where('purchase_order_id', $this->purchase_order->id)
+                    ->withTrashed()
+                    ->first();
+
+                if($invitation){
+                    $invitation->restore();
+                    return $this->purchase_order;
+                }
+            }
+
+            $ii = PurchaseOrderInvitation::create($this->purchase_order->company_id, $this->purchase_order->user_id);
+            $ii->key = $this->createDbHash($this->purchase_order->company->db);
+            $ii->purchase_order_id = $this->purchase_order->id;
+            $ii->vendor_contact_id = $contact->id;
+            $ii->save();
+        }
+
+
+        return $this->purchase_order;
+    }
+}
diff --git a/app/Services/PurchaseOrder/MarkSent.php b/app/Services/PurchaseOrder/MarkSent.php
new file mode 100644
index 000000000000..fe51346066d0
--- /dev/null
+++ b/app/Services/PurchaseOrder/MarkSent.php
@@ -0,0 +1,45 @@
+<?php
+
+
+namespace App\Services\PurchaseOrder;
+
+
+use App\Events\PurchaseOrder\PurchaseOrderWasMarkedSent;
+use App\Models\PurchaseOrder;
+use App\Utils\Ninja;
+
+class MarkSent
+{
+    private $client;
+
+    private $purchase_order;
+
+    public function __construct($client, $purchase_order)
+    {
+        $this->client = $client;
+        $this->purchase_order = $purchase_order;
+    }
+
+    public function run()
+    {
+
+        /* Return immediately if status is not draft */
+        if ($this->purchase_order->status_id != PurchaseOrder::STATUS_DRAFT) {
+            return $this->purchase_order;
+        }
+
+        $this->purchase_order->markInvitationsSent();
+
+        $this->purchase_order
+            ->service()
+            ->setStatus(PurchaseOrder::STATUS_SENT)
+            ->applyNumber()
+            //  ->adjustBalance($this->purchase_order->amount)
+            //  ->touchPdf()
+            ->save();
+
+        event(new PurchaseOrderWasMarkedSent($this->purchase_order, $this->purchase_order->company, Ninja::eventVars(auth()->user() ? auth()->user()->id : null)));
+
+        return $this->purchase_order;
+    }
+}
diff --git a/app/Services/PurchaseOrder/PurchaseOrderService.php b/app/Services/PurchaseOrder/PurchaseOrderService.php
index ffb2cb84d164..b86ced3750c7 100644
--- a/app/Services/PurchaseOrder/PurchaseOrderService.php
+++ b/app/Services/PurchaseOrder/PurchaseOrderService.php
@@ -52,6 +52,30 @@ class PurchaseOrderService
             $this->purchase_order->public_notes = $this->purchase_order->client->public_notes;
 
 
+        return $this;
+    }
+
+    public function setStatus($status)
+    {
+        $this->purchase_order->status_id = $status;
+
+        return $this;
+    }
+
+    public function markSent()
+    {
+        $this->purchase_order = (new MarkSent($this->purchase_order->client, $this->purchase_order))->run();
+
+        return $this;
+    }
+    /**
+     * Applies the purchase order  number.
+     * @return $this PurchaseOrderService object
+     */
+    public function applyNumber()
+    {
+        $this->purchase_order = (new ApplyNumber($this->purchase_order->client, $this->purchase_order))->run();
+
         return $this;
     }
 }
diff --git a/app/Transformers/PurchaseOrderInvitationTransformer.php b/app/Transformers/PurchaseOrderInvitationTransformer.php
new file mode 100644
index 000000000000..95187cc81c2c
--- /dev/null
+++ b/app/Transformers/PurchaseOrderInvitationTransformer.php
@@ -0,0 +1,32 @@
+<?php
+
+
+namespace App\Transformers;
+
+
+use App\Models\PurchaseOrderInvitation;
+use App\Utils\Traits\MakesHash;
+
+class PurchaseOrderInvitationTransformer extends EntityTransformer
+{
+    use MakesHash;
+
+    public function transform(PurchaseOrderInvitation $invitation)
+    {
+        return [
+            'id' => $this->encodePrimaryKey($invitation->id),
+            'vendor_contact_id' => $this->encodePrimaryKey($invitation->vendor_contact_id),
+            'key' => $invitation->key,
+            'link' => $invitation->getLink() ?: '',
+            'sent_date' => $invitation->sent_date ?: '',
+            'viewed_date' => $invitation->viewed_date ?: '',
+            'opened_date' => $invitation->opened_date ?: '',
+            'updated_at' => (int)$invitation->updated_at,
+            'archived_at' => (int)$invitation->deleted_at,
+            'created_at' => (int)$invitation->created_at,
+            'email_status' => $invitation->email_status ?: '',
+            'email_error' => (string)$invitation->email_error,
+        ];
+    }
+
+}
diff --git a/app/Transformers/PurchaseOrderTransformer.php b/app/Transformers/PurchaseOrderTransformer.php
index aef5ea1d6552..332879037ab2 100644
--- a/app/Transformers/PurchaseOrderTransformer.php
+++ b/app/Transformers/PurchaseOrderTransformer.php
@@ -13,12 +13,24 @@ namespace App\Transformers;
 
 
 use App\Models\PurchaseOrder;
+use App\Models\PurchaseOrderInvitation;
 use App\Utils\Traits\MakesHash;
 
 class PurchaseOrderTransformer extends EntityTransformer
 {
     use MakesHash;
 
+    protected $defaultIncludes = [
+        'invitations',
+    ];
+
+    public function includeInvitations(PurchaseOrder $purchase_order)
+    {
+        $transformer = new PurchaseOrderInvitationTransformer($this->serializer);
+
+        return $this->includeCollection($purchase_order->invitations, $transformer, PurchaseOrderInvitation::class);
+    }
+
     public function transform(PurchaseOrder $purchase_order)
     {
         return [
@@ -26,19 +38,18 @@ class PurchaseOrderTransformer extends EntityTransformer
             'user_id' => $this->encodePrimaryKey($purchase_order->user_id),
             'project_id' => $this->encodePrimaryKey($purchase_order->project_id),
             'assigned_user_id' => $this->encodePrimaryKey($purchase_order->assigned_user_id),
-            'vendor_id' => (string) $this->encodePrimaryKey($purchase_order->vendor_id),
-            'amount' => (float) $purchase_order->amount,
-            'balance' => (float) $purchase_order->balance,
-            'client_id' => (string) $this->encodePrimaryKey($purchase_order->client_id),
-            'vendor_id' => (string) $this->encodePrimaryKey($purchase_order->vendor_id),
-            'status_id' => (string) ($purchase_order->status_id ?: 1),
-            'design_id' => (string) $this->encodePrimaryKey($purchase_order->design_id),
-            'created_at' => (int) $purchase_order->created_at,
-            'updated_at' => (int) $purchase_order->updated_at,
-            'archived_at' => (int) $purchase_order->deleted_at,
-            'is_deleted' => (bool) $purchase_order->is_deleted,
+            'vendor_id' => (string)$this->encodePrimaryKey($purchase_order->vendor_id),
+            'amount' => (float)$purchase_order->amount,
+            'balance' => (float)$purchase_order->balance,
+            'client_id' => (string)$this->encodePrimaryKey($purchase_order->client_id),
+            'status_id' => (string)($purchase_order->status_id ?: 1),
+            'design_id' => (string)$this->encodePrimaryKey($purchase_order->design_id),
+            'created_at' => (int)$purchase_order->created_at,
+            'updated_at' => (int)$purchase_order->updated_at,
+            'archived_at' => (int)$purchase_order->deleted_at,
+            'is_deleted' => (bool)$purchase_order->is_deleted,
             'number' => $purchase_order->number ?: '',
-            'discount' => (float) $purchase_order->discount,
+            'discount' => (float)$purchase_order->discount,
             'po_number' => $purchase_order->po_number ?: '',
             'date' => $purchase_order->date ?: '',
             'last_sent_date' => $purchase_order->last_sent_date ?: '',
@@ -51,36 +62,36 @@ class PurchaseOrderTransformer extends EntityTransformer
             'terms' => $purchase_order->terms ?: '',
             'public_notes' => $purchase_order->public_notes ?: '',
             'private_notes' => $purchase_order->private_notes ?: '',
-            'uses_inclusive_taxes' => (bool) $purchase_order->uses_inclusive_taxes,
+            'uses_inclusive_taxes' => (bool)$purchase_order->uses_inclusive_taxes,
             'tax_name1' => $purchase_order->tax_name1 ? $purchase_order->tax_name1 : '',
-            'tax_rate1' => (float) $purchase_order->tax_rate1,
+            'tax_rate1' => (float)$purchase_order->tax_rate1,
             'tax_name2' => $purchase_order->tax_name2 ? $purchase_order->tax_name2 : '',
-            'tax_rate2' => (float) $purchase_order->tax_rate2,
+            'tax_rate2' => (float)$purchase_order->tax_rate2,
             'tax_name3' => $purchase_order->tax_name3 ? $purchase_order->tax_name3 : '',
-            'tax_rate3' => (float) $purchase_order->tax_rate3,
-            'total_taxes' => (float) $purchase_order->total_taxes,
-            'is_amount_discount' => (bool) ($purchase_order->is_amount_discount ?: false),
+            'tax_rate3' => (float)$purchase_order->tax_rate3,
+            'total_taxes' => (float)$purchase_order->total_taxes,
+            'is_amount_discount' => (bool)($purchase_order->is_amount_discount ?: false),
             'footer' => $purchase_order->footer ?: '',
-            'partial' => (float) ($purchase_order->partial ?: 0.0),
+            'partial' => (float)($purchase_order->partial ?: 0.0),
             'partial_due_date' => $purchase_order->partial_due_date ?: '',
-            'custom_value1' => (string) $purchase_order->custom_value1 ?: '',
-            'custom_value2' => (string) $purchase_order->custom_value2 ?: '',
-            'custom_value3' => (string) $purchase_order->custom_value3 ?: '',
-            'custom_value4' => (string) $purchase_order->custom_value4 ?: '',
-            'has_tasks' => (bool) $purchase_order->has_tasks,
-            'has_expenses' => (bool) $purchase_order->has_expenses,
-            'custom_surcharge1' => (float) $purchase_order->custom_surcharge1,
-            'custom_surcharge2' => (float) $purchase_order->custom_surcharge2,
-            'custom_surcharge3' => (float) $purchase_order->custom_surcharge3,
-            'custom_surcharge4' => (float) $purchase_order->custom_surcharge4,
-            'custom_surcharge_tax1' => (bool) $purchase_order->custom_surcharge_tax1,
-            'custom_surcharge_tax2' => (bool) $purchase_order->custom_surcharge_tax2,
-            'custom_surcharge_tax3' => (bool) $purchase_order->custom_surcharge_tax3,
-            'custom_surcharge_tax4' => (bool) $purchase_order->custom_surcharge_tax4,
-            'line_items' => $purchase_order->line_items ?: (array) [],
+            'custom_value1' => (string)$purchase_order->custom_value1 ?: '',
+            'custom_value2' => (string)$purchase_order->custom_value2 ?: '',
+            'custom_value3' => (string)$purchase_order->custom_value3 ?: '',
+            'custom_value4' => (string)$purchase_order->custom_value4 ?: '',
+            'has_tasks' => (bool)$purchase_order->has_tasks,
+            'has_expenses' => (bool)$purchase_order->has_expenses,
+            'custom_surcharge1' => (float)$purchase_order->custom_surcharge1,
+            'custom_surcharge2' => (float)$purchase_order->custom_surcharge2,
+            'custom_surcharge3' => (float)$purchase_order->custom_surcharge3,
+            'custom_surcharge4' => (float)$purchase_order->custom_surcharge4,
+            'custom_surcharge_tax1' => (bool)$purchase_order->custom_surcharge_tax1,
+            'custom_surcharge_tax2' => (bool)$purchase_order->custom_surcharge_tax2,
+            'custom_surcharge_tax3' => (bool)$purchase_order->custom_surcharge_tax3,
+            'custom_surcharge_tax4' => (bool)$purchase_order->custom_surcharge_tax4,
+            'line_items' => $purchase_order->line_items ?: (array)[],
             'entity_type' => 'credit',
-            'exchange_rate' => (float) $purchase_order->exchange_rate,
-            'paid_to_date' => (float) $purchase_order->paid_to_date,
+            'exchange_rate' => (float)$purchase_order->exchange_rate,
+            'paid_to_date' => (float)$purchase_order->paid_to_date,
             'subscription_id' => $this->encodePrimaryKey($purchase_order->subscription_id),
         ];
     }
diff --git a/app/Utils/Traits/GeneratesCounter.php b/app/Utils/Traits/GeneratesCounter.php
index b9606621246a..3dd2bcefb330 100644
--- a/app/Utils/Traits/GeneratesCounter.php
+++ b/app/Utils/Traits/GeneratesCounter.php
@@ -18,6 +18,7 @@ use App\Models\Expense;
 use App\Models\Invoice;
 use App\Models\Payment;
 use App\Models\Project;
+use App\Models\PurchaseOrder;
 use App\Models\Quote;
 use App\Models\RecurringExpense;
 use App\Models\RecurringInvoice;
@@ -44,8 +45,8 @@ trait GeneratesCounter
 
         $is_client_counter = false;
 
-        $counter_string = $this->getEntityCounter($entity, $client);  
-        $pattern = $this->getNumberPattern($entity, $client);  
+        $counter_string = $this->getEntityCounter($entity, $client);
+        $pattern = $this->getNumberPattern($entity, $client);
 
         if ((strpos($pattern, 'clientCounter') !== false) || (strpos($pattern, 'client_counter') !==false) ) {
 
@@ -71,9 +72,9 @@ trait GeneratesCounter
             $counter_entity = $client->company;
         }
 
-        //If it is a quote - we need to 
+        //If it is a quote - we need to
         $pattern = $this->getNumberPattern($entity, $client);
-        
+
         if(strlen($pattern) > 1 && (stripos($pattern, 'counter') === false)){
             $pattern = $pattern.'{$counter}';
         }
@@ -127,9 +128,9 @@ trait GeneratesCounter
                 break;
             case Quote::class:
 
-                if ($this->hasSharedCounter($client, 'quote')) 
+                if ($this->hasSharedCounter($client, 'quote'))
                     return 'invoice_number_counter';
-                
+
                 return 'quote_number_counter';
                 break;
             case RecurringInvoice::class:
@@ -145,14 +146,17 @@ trait GeneratesCounter
                 return 'payment_number_counter';
                 break;
             case Credit::class:
-                if ($this->hasSharedCounter($client, 'credit')) 
+                if ($this->hasSharedCounter($client, 'credit'))
                     return 'invoice_number_counter';
-            
+
                 return 'credit_number_counter';
                 break;
             case Project::class:
                 return 'project_number_counter';
                 break;
+            case PurchaseOrder::class:
+                return 'purchase_order_number_counter';
+                break;
 
             default:
                 return 'default_number_counter';
@@ -188,6 +192,20 @@ trait GeneratesCounter
 
         return $this->replaceUserVars($credit, $entity_number);
 
+    }
+    /**
+     * Gets the next purchase order number.
+     *
+     * @param PurchaseOrder $purchase_order  The purchase order
+     *
+     * @return     string              The next purchase order number.
+     */
+    public function getNextPurchaseOrderNumber(Client $client, ?PurchaseOrder $purchase_order) :string
+    {
+        $entity_number = $this->getNextEntityNumber(PurchaseOrder::class, $client);
+
+        return $this->replaceUserVars($purchase_order, $entity_number);
+
     }
 
     /**
@@ -385,7 +403,7 @@ trait GeneratesCounter
      *
      * @return     bool             True if has shared counter, False otherwise.
      */
-    public function hasSharedCounter(Client $client, string $type = 'quote') : bool 
+    public function hasSharedCounter(Client $client, string $type = 'quote') : bool
     {
         if($type == 'quote')
             return (bool) $client->getSetting('shared_invoice_quote_counter');
@@ -438,9 +456,9 @@ trait GeneratesCounter
     public function checkNumberAvailable($class, $entity, $number) :bool
     {
 
-        if ($entity = $class::whereCompanyId($entity->company_id)->whereNumber($number)->withTrashed()->exists()) 
+        if ($entity = $class::whereCompanyId($entity->company_id)->whereNumber($number)->withTrashed()->exists())
             return false;
-        
+
         return true;
 
     }
@@ -504,7 +522,7 @@ trait GeneratesCounter
 
         if($reset_counter_frequency == 0)
             return;
-        
+
         $timezone = Timezone::find($client->getSetting('timezone_id'));
 
         $reset_date = Carbon::parse($client->getSetting('reset_counter_date'), $timezone->name);
@@ -558,6 +576,7 @@ trait GeneratesCounter
         $settings->invoice_number_counter = 1;
         $settings->quote_number_counter = 1;
         $settings->credit_number_counter = 1;
+        $settings->purchase_order_number_counter = 1;
 
         $client->company->settings = $settings;
         $client->company->save();
@@ -622,6 +641,7 @@ trait GeneratesCounter
         $settings->task_number_counter = 1;
         $settings->expense_number_counter = 1;
         $settings->recurring_expense_number_counter =1;
+        $settings->purchase_order_number_counter = 1;
 
         $company->settings = $settings;
         $company->save();
@@ -644,7 +664,7 @@ trait GeneratesCounter
 
         $search = [];
         $replace = [];
-        
+
         $search[] = '{$counter}';
         $replace[] = $counter;
 
@@ -659,7 +679,7 @@ trait GeneratesCounter
 
         $search[] = '{$year}';
         $replace[] = Carbon::now($entity->company->timezone()->name)->format('Y');
-        
+
         if (strstr($pattern, '{$user_id}') || strstr($pattern, '{$userId}')) {
             $user_id = $entity->user_id ? $entity->user_id : 0;
             $search[] = '{$user_id}';
@@ -683,7 +703,7 @@ trait GeneratesCounter
             $search[] = '{$vendor_id_number}';
             $replace[] = $entity->id_number;
         }
-        
+
         if ($entity instanceof Expense) {
             if ($entity->vendor) {
                 $search[] = '{$vendor_id_number}';
@@ -708,7 +728,7 @@ trait GeneratesCounter
             $search[] = '{$expense_id_number}';
             $replace[] = $entity->id_number;
         }
-        
+
         if ($entity->client || ($entity instanceof Client)) {
             $client = $entity->client ?: $entity;
 
diff --git a/database/factories/PurchaseOrderInvitationFactory.php b/database/factories/PurchaseOrderInvitationFactory.php
new file mode 100644
index 000000000000..d2051c0c8d88
--- /dev/null
+++ b/database/factories/PurchaseOrderInvitationFactory.php
@@ -0,0 +1,31 @@
+<?php
+
+
+namespace Database\Factories;
+
+
+use App\Models\PurchaseOrderInvitation;
+use Illuminate\Database\Eloquent\Factories\Factory;
+use Illuminate\Support\Str;
+
+class PurchaseOrderInvitationFactory extends Factory
+{
+    /**
+     * The name of the factory's corresponding model.
+     *
+     * @var string
+     */
+    protected $model = PurchaseOrderInvitation::class;
+
+    /**
+     * Define the model's default state.
+     *
+     * @return array
+     */
+    public function definition()
+    {
+        return [
+            'key' => Str::random(40),
+        ];
+    }
+}
diff --git a/database/migrations/2022_06_01_224339_create_purchase_order_invitations_table.php b/database/migrations/2022_06_01_224339_create_purchase_order_invitations_table.php
new file mode 100644
index 000000000000..984e6c6cd634
--- /dev/null
+++ b/database/migrations/2022_06_01_224339_create_purchase_order_invitations_table.php
@@ -0,0 +1,53 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+class CreatePurchaseOrderInvitationsTable extends Migration
+{
+    /**
+     * Run the migrations.
+     *
+     * @return void
+     */
+    public function up()
+    {
+        Schema::create('purchase_order_invitations', function (Blueprint $table) {
+            $table->id();
+            $table->unsignedInteger('company_id')->index();
+            $table->unsignedInteger('user_id');
+            $table->unsignedInteger('vendor_contact_id')->unique();
+            $table->unsignedBigInteger('purchase_order_id')->index()->unique();
+            $table->string('key')->index();
+            $table->string('transaction_reference')->nullable();
+            $table->string('message_id')->nullable()->index();
+            $table->mediumText('email_error')->nullable();
+            $table->text('signature_base64')->nullable();
+            $table->datetime('signature_date')->nullable();
+
+            $table->datetime('sent_date')->nullable();
+            $table->datetime('viewed_date')->nullable();
+            $table->datetime('opened_date')->nullable();
+
+            $table->foreign('user_id')->references('id')->on('users')->onDelete('cascade')->onUpdate('cascade');
+            $table->foreign('vendor_contact_id')->references('id')->on('vendor_contacts')->onDelete('cascade')->onUpdate('cascade');
+            $table->foreign('purchase_order_id')->references('id')->on('purchase_orders')->onDelete('cascade')->onUpdate('cascade');
+            $table->foreign('company_id')->references('id')->on('companies')->onDelete('cascade')->onUpdate('cascade');
+
+            $table->timestamps(6);
+            $table->softDeletes('deleted_at', 6);
+
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     *
+     * @return void
+     */
+    public function down()
+    {
+        Schema::dropIfExists('purchase_order_invitations');
+    }
+}
diff --git a/tests/Feature/PurchaseOrderTest.php b/tests/Feature/PurchaseOrderTest.php
index 69504545a804..63799022b7aa 100644
--- a/tests/Feature/PurchaseOrderTest.php
+++ b/tests/Feature/PurchaseOrderTest.php
@@ -37,6 +37,7 @@ class PurchaseOrderTest extends TestCase
         Model::reguard();
 
         $this->makeTestData();
+
     }
 
     public function testPurchaseOrderRest()
@@ -44,18 +45,18 @@ class PurchaseOrderTest extends TestCase
         $response = $this->withHeaders([
             'X-API-SECRET' => config('ninja.api_secret'),
             'X-API-TOKEN' => $this->token,
-        ])->get('/api/v1/purchase_orders/'.$this->encodePrimaryKey($this->purchase_order->id));
+        ])->get('/api/v1/purchase_orders/' . $this->encodePrimaryKey($this->purchase_order->id));
 
         $response->assertStatus(200);
 
         $response = $this->withHeaders([
             'X-API-SECRET' => config('ninja.api_secret'),
             'X-API-TOKEN' => $this->token,
-        ])->get('/api/v1/purchase_orders/'.$this->encodePrimaryKey($this->purchase_order->id).'/edit');
+        ])->get('/api/v1/purchase_orders/' . $this->encodePrimaryKey($this->purchase_order->id) . '/edit');
 
         $response->assertStatus(200);
 
-        $credit_update = [
+        $purchase_order_update = [
             'tax_name1' => 'dippy',
         ];
 
@@ -64,14 +65,14 @@ class PurchaseOrderTest extends TestCase
         $response = $this->withHeaders([
             'X-API-SECRET' => config('ninja.api_secret'),
             'X-API-TOKEN' => $this->token,
-        ])->put('/api/v1/purchase_orders/'.$this->encodePrimaryKey($this->purchase_order->id), $credit_update)
+        ])->put('/api/v1/purchase_orders/' . $this->encodePrimaryKey($this->purchase_order->id), $purchase_order_update)
             ->assertStatus(200);
     }
+
     public function testPostNewPurchaseOrder()
     {
         $purchase_order = [
             'status_id' => 1,
-            'number' => 'dfdfd',
             'discount' => 0,
             'is_amount_discount' => 1,
             'number' => '34343xx43',
@@ -91,20 +92,21 @@ class PurchaseOrderTest extends TestCase
         ])->post('/api/v1/purchase_orders/', $purchase_order)
             ->assertStatus(200);
     }
+
     public function testPurchaseOrderDelete()
     {
         $response = $this->withHeaders([
             'X-API-SECRET' => config('ninja.api_secret'),
             'X-API-TOKEN' => $this->token,
-        ])->delete('/api/v1/purchase_orders/'.$this->encodePrimaryKey($this->purchase_order->id));
+        ])->delete('/api/v1/purchase_orders/' . $this->encodePrimaryKey($this->purchase_order->id));
 
         $response->assertStatus(200);
     }
+
     public function testPurchaseOrderUpdate()
     {
         $data = [
             'status_id' => 1,
-            'number' => 'dfdfd',
             'discount' => 0,
             'is_amount_discount' => 1,
             'number' => '3434343',
@@ -121,14 +123,14 @@ class PurchaseOrderTest extends TestCase
         $response = $this->withHeaders([
             'X-API-SECRET' => config('ninja.api_secret'),
             'X-API-TOKEN' => $this->token,
-        ])->put('/api/v1/purchase_orders/'.$this->encodePrimaryKey($this->purchase_order->id), $data);
+        ])->put('/api/v1/purchase_orders/' . $this->encodePrimaryKey($this->purchase_order->id), $data);
 
         $response->assertStatus(200);
 
         $response = $this->withHeaders([
             'X-API-SECRET' => config('ninja.api_secret'),
             'X-API-TOKEN' => $this->token,
-        ])->put('/api/v1/purchase_orders/'.$this->encodePrimaryKey($this->purchase_order->id), $data);
+        ])->put('/api/v1/purchase_orders/' . $this->encodePrimaryKey($this->purchase_order->id), $data);
 
         $response->assertStatus(200);
 
diff --git a/tests/MockAccountData.php b/tests/MockAccountData.php
index 0dddbaa32df2..2bb170b9388b 100644
--- a/tests/MockAccountData.php
+++ b/tests/MockAccountData.php
@@ -36,6 +36,8 @@ use App\Models\GroupSetting;
 use App\Models\InvoiceInvitation;
 use App\Models\Product;
 use App\Models\Project;
+use App\Models\PurchaseOrder;
+use App\Models\PurchaseOrderInvitation;
 use App\Models\Quote;
 use App\Models\QuoteInvitation;
 use App\Models\RecurringExpense;
@@ -476,6 +478,26 @@ trait MockAccountData
         $this->purchase_order->save();
 
 
+        PurchaseOrderInvitation::factory()->create([
+            'user_id' => $user_id,
+            'company_id' => $this->company->id,
+            'vendor_contact_id' => $vendor_contact->id,
+            'purchase_order_id' => $this->purchase_order->id,
+        ]);
+
+
+
+        $purchase_order_invitations = PurchaseOrderInvitation::whereCompanyId($this->purchase_order->company_id)
+            ->wherePurchaseOrderId($this->purchase_order->id);
+
+        $this->purchase_order->setRelation('invitations', $purchase_order_invitations);
+
+        $this->purchase_order->service()->markSent();
+
+        $this->purchase_order->setRelation('client', $this->client);
+        $this->purchase_order->setRelation('company', $this->company);
+
+        $this->purchase_order->save();
 
 
         $this->credit = CreditFactory::create($this->company->id, $user_id);