diff --git a/fillpdf.api.php b/fillpdf.api.php
index a4319d0567fab975e1da18f80c498ab2cd633591..fc8e1f5aa00307202973b6e9cbfbef07589a2b9e 100644
--- a/fillpdf.api.php
+++ b/fillpdf.api.php
@@ -5,11 +5,30 @@
  * Hooks related to FillPDF module.
  */
 
+use Drupal\fillpdf\Form\FillPdfFormForm;
+
 /**
  * @addtogroup hooks
  * @{
  */
 
+/**
+ * Alter a FillPdfFormForm prior to building its edit form.
+ *
+ * This is triggered in FillPdfFormForm::form().
+ *
+ * @param Drupal\fillpdf\Form\FillPdfFormForm $fillpdf_form_form
+ *   The FillPdfFormForm object to alter.
+ */
+function hook_fillpdf_form_form_pre_form_build_alter(FillPdfFormForm $fillpdf_form_form): void {
+  // Set the default entity type for any FillPDF form to 'webform'.
+  $fillpdf_form = $fillpdf_form_form->getEntity();
+  $default_entity_type = $fillpdf_form->getDefaultEntityType();
+  if (!$default_entity_type) {
+    $fillpdf_form->set('default_entity_type', 'webform')->save();
+  }
+}
+
 /**
  * Alter the $context in HandlePdfController::populatePdf().
  *
diff --git a/src/Form/FillPdfFormForm.php b/src/Form/FillPdfFormForm.php
index a9dd549e66461c0542900851adfd649a0fe776a9..86539aded1d89960dc0f746cd73509e21a74f454 100644
--- a/src/Form/FillPdfFormForm.php
+++ b/src/Form/FillPdfFormForm.php
@@ -144,6 +144,9 @@ class FillPdfFormForm extends ContentEntityForm {
    * {@inheritdoc}
    */
   public function form(array $form, FormStateInterface $form_state) {
+    // Create hook_fillpdf_form_form_pre_form_build_alter().
+    $this->moduleHandler->alter('fillpdf_form_form_pre_form_build', $this);
+
     $form = parent::form($form, $form_state);
 
     /** @var \Drupal\fillpdf\FillPdfFormInterface $fillpdf_form */