diff --git a/modules/checkout/commerce_checkout.module b/modules/checkout/commerce_checkout.module
index a792b11b34..6ae4e5269d 100644
--- a/modules/checkout/commerce_checkout.module
+++ b/modules/checkout/commerce_checkout.module
@@ -25,6 +25,7 @@ function commerce_checkout_theme() {
     'commerce_checkout_completion_message' => [
       'variables' => [
         'order_entity' => NULL,
+        'completion_messages' => NULL,
         'payment_instructions' => NULL,
       ],
     ],
diff --git a/modules/checkout/src/Plugin/Commerce/CheckoutPane/CompletionMessage.php b/modules/checkout/src/Plugin/Commerce/CheckoutPane/CompletionMessage.php
index fef9352aff..a0094251b9 100644
--- a/modules/checkout/src/Plugin/Commerce/CheckoutPane/CompletionMessage.php
+++ b/modules/checkout/src/Plugin/Commerce/CheckoutPane/CompletionMessage.php
@@ -2,6 +2,8 @@
 
 namespace Drupal\commerce_checkout\Plugin\Commerce\CheckoutPane;
 
+use Drupal\commerce_checkout\Plugin\Commerce\CheckoutFlow\CheckoutFlowInterface;
+use Drupal\Core\Entity\EntityTypeManagerInterface;
 use Drupal\Core\Form\FormStateInterface;
 
 /**
@@ -15,14 +17,79 @@
  */
 class CompletionMessage extends CheckoutPaneBase {
 
+  /**
+   * @var \Drupal\commerce_checkout\Plugin\Commerce\CheckoutPane\CompletionMessages
+   */
+  private $completionMessags;
+
+  /**
+   * {@inheritdoc}
+   */
+  public function __construct(array $configuration, $plugin_id, $plugin_definition, CheckoutFlowInterface $checkout_flow, EntityTypeManagerInterface $entity_type_manager) {
+    parent::__construct($configuration, $plugin_id, $plugin_definition, $checkout_flow, $entity_type_manager);
+    $this->completionMessags = new CompletionMessages();
+  }
+
   /**
    * {@inheritdoc}
    */
   public function buildPaneForm(array $pane_form, FormStateInterface $form_state, array &$complete_form) {
+    $this->preparePaneForm();
+
     $pane_form['#theme'] = 'commerce_checkout_completion_message';
     $pane_form['#order_entity'] = $this->order;
+    $pane_form['#completion_messages'] = $this->completionMessags;
 
     return $pane_form;
   }
 
+  /**
+   * Prepares the necessary data for the completion messages.
+   */
+  public function preparePaneForm() {
+    $this->populateCompletionMessages();
+  }
+
+  /**
+   * Gets the completion messages.
+   */
+  private function populateCompletionMessages() {
+    $this->populateCompletionMessagesWithAnonymousMessage();
+    $this->populateCompletionMessagesWithAuthenticatedMessage();
+
+    $this->allowOthersToModifyMessages();
+  }
+
+  /**
+   * Gets the default completion message.
+   */
+  private function populateCompletionMessagesWithAnonymousMessage() {
+    if (\Drupal::currentUser()->isAnonymous()) {
+      $this->completionMessags->addMessage($this->t('Your order number is @number.', ['@number' => $this->order->id()]));
+      $this->completionMessags->addMessage($this->t('You can view your order on your account page when logged in.'));
+    }
+  }
+
+  /**
+   * Populate the completion messages with the logged in message.
+   */
+  private function populateCompletionMessagesWithAuthenticatedMessage() {
+    if (\Drupal::currentUser()->isAuthenticated()) {
+      $this->completionMessags->addMessage(
+        $this->t(
+          'Your order number is %order_number_with_link.',
+          ['%order_number_with_link' => $this->order->toLink($this->order->id())]
+        )
+      );
+    }
+  }
+
+  /**
+   * Allow other modules to alter the messages.
+   */
+  private function allowOthersToModifyMessages() {
+    \Drupal::moduleHandler()
+      ->alter('checkout_completion_messages', $this->completionMessags, $this->order);
+  }
+
 }
diff --git a/modules/checkout/src/Plugin/Commerce/CheckoutPane/CompletionMessages.php b/modules/checkout/src/Plugin/Commerce/CheckoutPane/CompletionMessages.php
new file mode 100644
index 0000000000..51af9655a4
--- /dev/null
+++ b/modules/checkout/src/Plugin/Commerce/CheckoutPane/CompletionMessages.php
@@ -0,0 +1,86 @@
+<?php
+
+namespace Drupal\commerce_checkout\Plugin\Commerce\CheckoutPane;
+
+use Drupal\Core\StringTranslation\TranslatableMarkup;
+
+/**
+ * Acts as a container to collect all completion messages.
+ *
+ * @package Drupal\commerce_checkout\Plugin\Commerce\CheckoutPane
+ */
+class CompletionMessages implements \Iterator, \Countable {
+
+  /**
+   * @var \Drupal\Core\StringTranslation\TranslatableMarkup[]
+   */
+  private $messages;
+
+  /**
+   * @var int
+   */
+  private $position;
+
+  /**
+   * Sets up the position to 0.
+   */
+  public function __construct() {
+    $this->position = 0;
+  }
+
+  /**
+   * Adds a message to the array.
+   *
+   * @param \Drupal\Core\StringTranslation\TranslatableMarkup $message
+   *   The message to add.
+   */
+  public function addMessage(TranslatableMarkup $message) {
+    $this->messages[] = $message;
+  }
+
+  /**
+   * Gets the current message.
+   *
+   * @return \Drupal\Core\StringTranslation\TranslatableMarkup
+   *   The current message.
+   */
+  public function current() {
+    return $this->messages[$this->position];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function next() {
+    ++$this->position;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function key() {
+    return $this->position;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function valid() {
+    return isset($this->messages[$this->position]);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function rewind() {
+    $this->position = 0;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function count() {
+    return count($this->messages);
+  }
+
+}
diff --git a/modules/checkout/templates/commerce-checkout-completion-message.html.twig b/modules/checkout/templates/commerce-checkout-completion-message.html.twig
index 5c8727f8bc..2b6fb3e9c0 100644
--- a/modules/checkout/templates/commerce-checkout-completion-message.html.twig
+++ b/modules/checkout/templates/commerce-checkout-completion-message.html.twig
@@ -11,6 +11,10 @@
  */
 #}
 <div class="checkout-complete">
+  {% for message in completion_messages %}
+    {{ message }} <br/>
+  {% endfor %}
+
   {{ 'Your order number is @number.'|t({'@number': order_entity.getOrderNumber}) }} <br>
   {{ 'You can view your order on your account page when logged in.'|t }} <br>
 
diff --git a/modules/checkout/tests/src/Functional/CheckoutOrderTest.php b/modules/checkout/tests/src/Functional/CheckoutOrderTest.php
index 7ed0ccbc54..ad4d8c296a 100644
--- a/modules/checkout/tests/src/Functional/CheckoutOrderTest.php
+++ b/modules/checkout/tests/src/Functional/CheckoutOrderTest.php
@@ -162,7 +162,7 @@ public function testGuestOrderCheckout() {
     $this->assertSession()->pageTextContains('Billing information');
     $this->assertSession()->pageTextContains('Order Summary');
     $this->submitForm([], 'Pay and complete purchase');
-    $this->assertSession()->pageTextContains('Your order number is 1. You can view your order on your account page when logged in.');
+    $this->assertSession()->pageTextContains('Your order number is 1.');
     $this->assertSession()->pageTextContains('0 items');
     // Test second order.
     $this->drupalGet($this->product->toUrl()->toString());
@@ -198,7 +198,7 @@ public function testGuestOrderCheckout() {
     $this->assertCheckoutProgressStep('Review');
 
     $this->submitForm([], 'Pay and complete purchase');
-    $this->assertSession()->pageTextContains('Your order number is 2. You can view your order on your account page when logged in.');
+    $this->assertSession()->pageTextContains('Your order number is 2.');
     $this->assertSession()->pageTextContains('0 items');
   }
 
diff --git a/modules/checkout/tests/src/Kernel/CompletionMessagesTest.php b/modules/checkout/tests/src/Kernel/CompletionMessagesTest.php
new file mode 100644
index 0000000000..6ad9f65221
--- /dev/null
+++ b/modules/checkout/tests/src/Kernel/CompletionMessagesTest.php
@@ -0,0 +1,52 @@
+<?php
+
+namespace Drupal\Tests\commerce_checkout\Kernel;
+
+use Drupal\commerce_checkout\Plugin\Commerce\CheckoutPane\CompletionMessages;
+use Drupal\Tests\commerce\Kernel\CommerceKernelTestBase;
+
+/**
+ * Tests the completion messages class.
+ *
+ * @covers \Drupal\commerce_checkout\Plugin\Commerce\CheckoutPane\CompletionMessages
+ *
+ * @group commerce
+ */
+class CompletionMessagesTest extends CommerceKernelTestBase {
+
+  /**
+   * @var \Drupal\commerce_checkout\Plugin\Commerce\CheckoutPane\CompletionMessages
+   */
+  private $completionMessages;
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setUp() {
+    parent::setUp();
+    $this->completionMessages = new CompletionMessages();
+  }
+
+  /**
+   * Tests add message method.
+   */
+  public function testAddMessage() {
+    $this->completionMessages->addMessage(t('Message 1'));
+    $this->completionMessages->addMessage(t('Message 2'));
+
+    $this->assertCount(2, $this->completionMessages);
+  }
+
+  /**
+   * Tests the messages iterator.
+   */
+  public function testMessagesIterator() {
+    $this->completionMessages->addMessage(t('Message 1'));
+    $this->completionMessages->addMessage(t('Message 2'));
+
+    $this->assertEquals('Message 1', $this->completionMessages->current()->render());
+    $this->completionMessages->next();
+    $this->assertEquals('Message 2', $this->completionMessages->current()->render());
+  }
+
+}
diff --git a/modules/payment/tests/src/FunctionalJavascript/PaymentCheckoutTest.php b/modules/payment/tests/src/FunctionalJavascript/PaymentCheckoutTest.php
index 31221e0d97..9e1619afa4 100644
--- a/modules/payment/tests/src/FunctionalJavascript/PaymentCheckoutTest.php
+++ b/modules/payment/tests/src/FunctionalJavascript/PaymentCheckoutTest.php
@@ -266,7 +266,7 @@ public function testCheckoutWithExistingPaymentMethod() {
     $this->assertSession()->pageTextContains('Frederick Pabst');
     $this->assertSession()->pageTextContains('Pabst Blue Ribbon Dr');
     $this->submitForm([], 'Pay and complete purchase');
-    $this->assertSession()->pageTextContains('Your order number is 1. You can view your order on your account page when logged in.');
+    $this->assertSession()->pageTextContains('Your order number is 1.');
 
     $order = Order::load(1);
     $this->assertEquals('onsite', $order->get('payment_gateway')->target_id);
@@ -317,7 +317,7 @@ public function testCheckoutWithNewPaymentMethod() {
     $this->assertSession()->pageTextContains('Johnny Appleseed');
     $this->assertSession()->pageTextContains('123 New York Drive');
     $this->submitForm([], 'Pay and complete purchase');
-    $this->assertSession()->pageTextContains('Your order number is 1. You can view your order on your account page when logged in.');
+    $this->assertSession()->pageTextContains('Your order number is 1.');
 
     $order = Order::load(1);
     $this->assertEquals('onsite', $order->get('payment_gateway')->target_id);
@@ -360,7 +360,7 @@ public function testCheckoutWithDeclinedPaymentMethod() {
     $this->assertSession()->pageTextContains('Visa ending in 1111');
     $this->assertSession()->pageTextContains('Expires 2/2020');
     $this->submitForm([], 'Pay and complete purchase');
-    $this->assertSession()->pageTextNotContains('Your order number is 1. You can view your order on your account page when logged in.');
+    $this->assertSession()->pageTextNotContains('Your order number is 1.');
     $this->assertSession()->pageTextContains('We encountered an error processing your payment method. Please verify your details and try again.');
     $this->assertSession()->addressEquals('checkout/1/order_information');
 
@@ -393,7 +393,7 @@ public function testCheckoutWithOffsiteRedirectPost() {
     $this->assertSession()->pageTextContains('Johnny Appleseed');
     $this->assertSession()->pageTextContains('123 New York Drive');
     $this->submitForm([], 'Pay and complete purchase');
-    $this->assertSession()->pageTextContains('Your order number is 1. You can view your order on your account page when logged in.');
+    $this->assertSession()->pageTextContains('Your order number is 1.');
     $order = Order::load(1);
     $this->assertEquals('offsite', $order->get('payment_gateway')->target_id);
 
@@ -440,7 +440,7 @@ public function testCheckoutWithOffsiteRedirectGet() {
     $this->assertSession()->pageTextContains('Johnny Appleseed');
     $this->assertSession()->pageTextContains('123 New York Drive');
     $this->submitForm([], 'Pay and complete purchase');
-    $this->assertSession()->pageTextContains('Your order number is 1. You can view your order on your account page when logged in.');
+    $this->assertSession()->pageTextContains('Your order number is 1.');
     $order = Order::load(1);
     $this->assertEquals('offsite', $order->get('payment_gateway')->target_id);
 
@@ -483,7 +483,7 @@ public function testFailedCheckoutWithOffsiteRedirectGet() {
     $this->assertSession()->pageTextContains('Johnny FAIL');
     $this->assertSession()->pageTextContains('123 New York Drive');
     $this->submitForm([], 'Pay and complete purchase');
-    $this->assertSession()->pageTextNotContains('Your order number is 1. You can view your order on your account page when logged in.');
+    $this->assertSession()->pageTextNotContains('Your order number is 1.');
     $this->assertSession()->pageTextContains('We encountered an unexpected error processing your payment. Please try again later.');
     $this->assertSession()->addressEquals('checkout/1/order_information');
 
@@ -516,7 +516,7 @@ public function testCheckoutWithManual() {
     $this->assertSession()->pageTextContains('Johnny Appleseed');
     $this->assertSession()->pageTextContains('123 New York Drive');
     $this->submitForm([], 'Pay and complete purchase');
-    $this->assertSession()->pageTextContains('Your order number is 1. You can view your order on your account page when logged in.');
+    $this->assertSession()->pageTextContains('Your order number is 1.');
     $this->assertSession()->pageTextContains('Sample payment instructions.');
     $order = Order::load(1);
     $this->assertEquals('manual', $order->get('payment_gateway')->target_id);
diff --git a/modules/promotion/tests/src/FunctionalJavascript/CouponRedemptionPaneTest.php b/modules/promotion/tests/src/FunctionalJavascript/CouponRedemptionPaneTest.php
index 83cfd3a6d8..fb18d8ed1c 100644
--- a/modules/promotion/tests/src/FunctionalJavascript/CouponRedemptionPaneTest.php
+++ b/modules/promotion/tests/src/FunctionalJavascript/CouponRedemptionPaneTest.php
@@ -235,7 +235,7 @@ public function testCheckout() {
     $this->assertSession()->pageTextContains('$899.10');
 
     $this->submitForm([], 'Pay and complete purchase');
-    $this->assertSession()->pageTextContains('Your order number is 1. You can view your order on your account page when logged in.');
+    $this->assertSession()->pageTextContains('Your order number is 1.');
 
     $order_storage = $this->container->get('entity_type.manager')->getStorage('commerce_order');
     $order_storage->resetCache([$this->cart->id()]);
@@ -259,7 +259,7 @@ public function testCheckoutWithMainSubmit() {
     $this->assertSession()->pageTextContains('$899.10');
 
     $this->submitForm([], 'Pay and complete purchase');
-    $this->assertSession()->pageTextContains('Your order number is 1. You can view your order on your account page when logged in.');
+    $this->assertSession()->pageTextContains('Your order number is 1.');
 
     $order_storage = $this->container->get('entity_type.manager')->getStorage('commerce_order');
     $order_storage->resetCache([$this->cart->id()]);