diff --git a/src/Form/FillPdfFormFieldForm.php b/src/Form/FillPdfFormFieldForm.php
index b4de71e5e39b2cc472bc7be0db4a26b4d1832d8c..dc65f034564e5784033c336e11cfb10e3fe69c7c 100644
--- a/src/Form/FillPdfFormFieldForm.php
+++ b/src/Form/FillPdfFormFieldForm.php
@@ -3,40 +3,49 @@
 namespace Drupal\fillpdf\Form;
 
 use Drupal\Core\Entity\ContentEntityForm;
-use Drupal\Core\Entity\EntityManagerInterface;
+use Drupal\Core\Entity\EntityRepositoryInterface;
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\fillpdf\FillPdfAdminFormHelperInterface;
-use Drupal\fillpdf\FillPdfFormInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 
+/**
+ * Form controller for the FillPdfFormFieldForm edit form.
+ */
 class FillPdfFormFieldForm extends ContentEntityForm {
 
+  /**
+   * The FillPdf admin form helper.
+   *
+   * @var \Drupal\fillpdf\FillPdfAdminFormHelperInterface
+   */
   protected $adminFormHelper;
 
   /**
-   * The construct "magic method."
+   * Constructs a FillPdfFormFieldForm object.
    *
-   * @param \Drupal\Core\Entity\EntityManagerInterface $entity_manager
-   *   Injected service. Deprecated but still used in the parent class.
+   * @param \Drupal\Core\Entity\EntityRepositoryInterface $entity_repository
+   *   The entity repository service.
    * @param \Drupal\fillpdf\FillPdfAdminFormHelperInterface $admin_form_helper
-   *   Injected service.
+   *   FillPdf admin form helper service.
    */
-  public function __construct(EntityManagerInterface $entity_manager, FillPdfAdminFormHelperInterface $admin_form_helper) {
-    parent::__construct($entity_manager);
+  public function __construct(EntityRepositoryInterface $entity_repository, FillPdfAdminFormHelperInterface $admin_form_helper) {
+    parent::__construct($entity_repository);
     $this->adminFormHelper = $admin_form_helper;
   }
 
   /**
-   * @param \Symfony\Component\DependencyInjection\ContainerInterface $container
-   * @return static
+   * {@inheritdoc}
    */
   public static function create(ContainerInterface $container) {
     return new static(
-      $container->get('entity.manager'),
+      $container->get('entity.repository'),
       $container->get('fillpdf.admin_form_helper')
     );
   }
 
+  /**
+   * {@inheritdoc}
+   */
   public function form(array $form, FormStateInterface $form_state) {
     $form = parent::form($form, $form_state);
 
@@ -45,6 +54,9 @@ class FillPdfFormFieldForm extends ContentEntityForm {
     return $form;
   }
 
+  /**
+   * {@inheritdoc}
+   */
   public function save(array $form, FormStateInterface $form_state) {
     /** @var FillPdfFormInterface $entity */
     $entity = $this->entity;
diff --git a/src/Form/FillPdfFormForm.php b/src/Form/FillPdfFormForm.php
index a23344fdae7b179a5623a3121ee2fa7c3d3f2a4a..a0361c3e9bc2f9b680dc338083c4bf531427e93e 100644
--- a/src/Form/FillPdfFormForm.php
+++ b/src/Form/FillPdfFormForm.php
@@ -3,50 +3,96 @@
 namespace Drupal\fillpdf\Form;
 
 use Drupal\Core\Entity\ContentEntityForm;
-use Drupal\Core\Entity\EntityManagerInterface;
+use Drupal\Core\Entity\EntityRepositoryInterface;
 use Drupal\Core\File\FileSystemInterface;
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Url;
 use Drupal\file\Entity\File;
-use Drupal\file\FileInterface;
 use Drupal\fillpdf\Component\Utility\FillPdf;
 use Drupal\fillpdf\EntityHelper;
 use Drupal\fillpdf\FillPdfAdminFormHelperInterface;
-use Drupal\fillpdf\FillPdfFormFieldInterface;
-use Drupal\fillpdf\FillPdfFormInterface;
 use Drupal\fillpdf\FillPdfLinkManipulatorInterface;
 use Drupal\fillpdf\InputHelperInterface;
 use Drupal\fillpdf\SerializerInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
-use Symfony\Component\HttpFoundation\File\UploadedFile;
 
+/**
+ * Form controller for the FillPDFForm edit form.
+ */
 class FillPdfFormForm extends ContentEntityForm {
+
   use FillPdfFormUploadTrait;
 
-  /** @var \Drupal\fillpdf\FillPdfAdminFormHelperInterface */
+  /**
+   * The FillPdf admin form helper.
+   *
+   * @var \Drupal\fillpdf\FillPdfAdminFormHelperInterface
+   */
   protected $adminFormHelper;
 
-  /** @var \Drupal\fillpdf\FillPdfLinkManipulatorInterface */
+  /**
+   * The FillPdf link manipulator.
+   *
+   * @var \Drupal\fillpdf\FillPdfLinkManipulatorInterface
+   */
   protected $linkManipulator;
 
-  /** @var \Drupal\fillpdf\EntityHelper */
+  /**
+   * The FillPdf entity helper.
+   *
+   * @var \Drupal\fillpdf\EntityHelper
+   */
   protected $entityHelper;
 
-  /** @var \Drupal\fillpdf\InputHelperInterface */
+  /**
+   * The FillPdf link manipulator.
+   *
+   * @var \Drupal\fillpdf\InputHelperInterface
+   */
   protected $inputHelper;
 
-  /** @var \Drupal\fillpdf\SerializerInterface */
+  /**
+   * The FillPdf serializer.
+   *
+   * @var \Drupal\fillpdf\SerializerInterface
+   */
   protected $serializer;
 
-  /** @var \Drupal\Core\File\FileSystemInterface */
+  /**
+   * The file system service.
+   *
+   * @var \Drupal\Core\File\FileSystemInterface
+   */
   protected $fileSystem;
 
-  public function __construct(EntityManagerInterface $entity_manager, FillPdfAdminFormHelperInterface $admin_form_helper,
-                              FillPdfLinkManipulatorInterface $link_manipulator,
-                              EntityHelper $entity_helper, InputHelperInterface $input_helper,
-                              SerializerInterface $fillpdf_serializer, FileSystemInterface $file_system) {
-    $this->entityManager = $entity_manager;
-    parent::__construct($this->entityManager);
+  /**
+   * Constructs a FillPdfFormForm object.
+   *
+   * @param \Drupal\Core\Entity\EntityRepositoryInterface $entity_repository
+   *   The entity repository service.
+   * @param \Drupal\fillpdf\FillPdfAdminFormHelperInterface $admin_form_helper
+   *   FillPdf admin form helper.
+   * @param \Drupal\fillpdf\FillPdfLinkManipulatorInterface $link_manipulator
+   *   FillPdf link manipulator.
+   * @param \Drupal\fillpdf\EntityHelper $entity_helper
+   *   FillPdf entity helper.
+   * @param \Drupal\fillpdf\InputHelperInterface $input_helper
+   *   FillPdf link manipulator.
+   * @param \Drupal\fillpdf\SerializerInterface $fillpdf_serializer
+   *   FillPdf serializer.
+   * @param \Drupal\Core\File\FileSystemInterface $file_system
+   *   Helpers to operate on files and stream wrappers.
+   */
+  public function __construct(
+    EntityRepositoryInterface $entity_repository,
+    FillPdfAdminFormHelperInterface $admin_form_helper,
+    FillPdfLinkManipulatorInterface $link_manipulator,
+    EntityHelper $entity_helper,
+    InputHelperInterface $input_helper,
+    SerializerInterface $fillpdf_serializer,
+    FileSystemInterface $file_system
+  ) {
+    parent::__construct($entity_repository);
     $this->adminFormHelper = $admin_form_helper;
     $this->linkManipulator = $link_manipulator;
     $this->entityHelper = $entity_helper;
@@ -55,9 +101,12 @@ class FillPdfFormForm extends ContentEntityForm {
     $this->fileSystem = $file_system;
   }
 
+  /**
+   * {@inheritdoc}
+   */
   public static function create(ContainerInterface $container) {
     return new static(
-      $container->get('entity.manager'),
+      $container->get('entity.repository'),
       $container->get('fillpdf.admin_form_helper'),
       $container->get('fillpdf.link_manipulator'),
       $container->get('fillpdf.entity_helper'),
@@ -73,7 +122,7 @@ class FillPdfFormForm extends ContentEntityForm {
   public function form(array $form, FormStateInterface $form_state) {
     $form = parent::form($form, $form_state);
 
-    /** @var FillPdfFormInterface $entity */
+    /** @var \Drupal\fillpdf\FillPdfFormInterface $entity */
     $entity = $this->entity;
 
     $form['tokens'] = [
@@ -84,7 +133,7 @@ class FillPdfFormForm extends ContentEntityForm {
     ];
 
     $entity_types = [];
-    $entity_type_definitions = $this->entityManager->getDefinitions();
+    $entity_type_definitions = $this->entityTypeManager->getDefinitions();
 
     foreach ($entity_type_definitions as $machine_name => $definition) {
       $label = $definition->getLabel();
@@ -108,7 +157,7 @@ class FillPdfFormForm extends ContentEntityForm {
 
     $fid = $entity->id();
 
-    /** @var FileInterface $file_entity */
+    /** @var \Drupal\file\FileInterface $file_entity */
     $file_entity = File::load($entity->get('file')->first()->target_id);
     $pdf_info_weight = 0;
     $form['pdf_info'] = [
@@ -204,11 +253,14 @@ class FillPdfFormForm extends ContentEntityForm {
     return $form;
   }
 
+  /**
+   * {@inheritdoc}
+   */
   public function validateForm(array &$form, FormStateInterface $form_state) {
     parent::validateForm($form, $form_state);
     $files = $this->getRequest()->files->get('files');
 
-    /** @var UploadedFile|null $file_upload */
+    /** @var \Symfony\Component\HttpFoundation\File\UploadedFile|null $file_upload */
     $file_upload = array_key_exists('upload_pdf', $files) ? $files['upload_pdf'] : NULL;
     if ($file_upload) {
       $this->validatePdfUpload($form, $form_state, $file_upload);
@@ -219,7 +271,7 @@ class FillPdfFormForm extends ContentEntityForm {
    * {@inheritdoc}
    */
   public function save(array $form, FormStateInterface $form_state) {
-    /** @var FillPdfFormInterface $entity */
+    /** @var \Drupal\fillpdf\FillPdfFormInterface $entity */
     $entity = $this->getEntity();
 
     /** @var \Drupal\file\FileInterface $file */
@@ -229,7 +281,7 @@ class FillPdfFormForm extends ContentEntityForm {
       $existing_fields = $this->entityHelper->getFormFields($entity);
 
       // Delete existing fields.
-      /** @var FillPdfFormFieldInterface $existing_field */
+      /** @var \Drupal\fillpdf\FillPdfFormFieldInterface $existing_field */
       foreach ($existing_fields as $existing_field) {
         $existing_field->delete();
       }