diff --git a/media_entity.module b/media_entity.module
index d54f773..8d4cc02 100644
--- a/media_entity.module
+++ b/media_entity.module
@@ -6,6 +6,8 @@
  */
 
 use Drupal\Core\Routing\RouteMatchInterface;
+use Drupal\field\Entity\FieldConfig;
+use Drupal\media_entity\Entity\MediaBundle;
 
 /**
  * Implements hook_help().
@@ -82,3 +84,36 @@ function media_entity_copy_icons($source, $destination) {
     }
   }
 }
+
+/**
+ * Implements hook_ENTITY_TYPE_insert().
+ */
+function media_entity_media_bundle_insert(MediaBundle $media_bundle) {
+  // When creating new bundles, add also a source field, if configured to do so.
+  if (!$media_bundle->isSyncing() && empty($media_bundle->getTypeConfiguration()['source_field']) && $media_bundle->getCreateSourceField()) {
+    $media_type_manager = \Drupal::service('plugin.manager.media_entity.type');
+    $instance = $media_type_manager->createInstance($media_bundle->getType()->getPluginId(), $media_bundle->getTypeConfiguration());
+    $default_field = $instance->getDefaultSourceField();
+    if (!empty($default_field['storage'])) {
+      // Save the field storage and create the instance.
+      $default_field['storage']->save();
+      FieldConfig::create([
+        'entity_type' => 'media',
+        'field_name' => $default_field['field_name'],
+        'label' => $default_field['label'],
+        'required' => TRUE,
+        'bundle' => $media_bundle->id(),
+      ])->save();
+      // Make the field visible on the form display.
+      $form_display = entity_get_form_display('media', $media_bundle->id(), 'default');
+      $form_display->setComponent($default_field['field_name'], [
+        'type' => $default_field['field_widget'],
+      ])->save();
+      // Make the field visible on the media entity itself.
+      $dispaly = entity_get_display('media', $media_bundle->id(), 'default');
+      $dispaly->setComponent($default_field['field_name'], [
+        'type' => $default_field['field_formatter'],
+      ])->save();
+    }
+  }
+}
diff --git a/src/Entity/MediaBundle.php b/src/Entity/MediaBundle.php
index 8833f82..5227d50 100644
--- a/src/Entity/MediaBundle.php
+++ b/src/Entity/MediaBundle.php
@@ -2,8 +2,8 @@
 
 namespace Drupal\media_entity\Entity;
 
-use Drupal\Core\Entity\EntityDescriptionInterface;
 use Drupal\Core\Config\Entity\ConfigEntityBundleBase;
+use Drupal\Core\Entity\EntityDescriptionInterface;
 use Drupal\Core\Entity\EntityWithPluginCollectionInterface;
 use Drupal\Core\Plugin\DefaultSingleLazyPluginCollection;
 use Drupal\media_entity\MediaBundleInterface;
@@ -44,6 +44,7 @@ use Drupal\media_entity\MediaInterface;
  *     "type_configuration",
  *     "field_map",
  *     "status",
+ *     "create_source_field",
  *   },
  *   links = {
  *     "add-form" = "/admin/structure/media/add",
@@ -121,11 +122,18 @@ class MediaBundle extends ConfigEntityBundleBase implements MediaBundleInterface
   /**
    * Default status of this media bundle.
    *
-   * @var array
+   * @var bool
    */
   public $status = TRUE;
 
   /**
+   * A flag indicating if we should create a source field upon save.
+   *
+   * @var bool
+   */
+  public $create_source_field = TRUE;
+
+  /**
    * {@inheritdoc}
    */
   public function id() {
@@ -230,6 +238,13 @@ class MediaBundle extends ConfigEntityBundleBase implements MediaBundleInterface
   /**
    * {@inheritdoc}
    */
+  public function getCreateSourceField() {
+    return $this->create_source_field;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
   public function shouldCreateNewRevision() {
     return $this->new_revision;
   }
diff --git a/src/MediaBundleForm.php b/src/MediaBundleForm.php
index 36365f3..d50d22d 100644
--- a/src/MediaBundleForm.php
+++ b/src/MediaBundleForm.php
@@ -170,6 +170,22 @@ class MediaBundleForm extends EntityForm {
       $form['type_configuration'][$plugin->getPluginId()] += $instance->buildConfigurationForm([], $form_state);
     }
 
+    // Add a checkbox to allow the field being created automattically on save.
+    if (!empty($form['type_configuration'][$plugin->getPluginId()]['source_field']) && empty($plugin_configuration['source_field'])) {
+      $has_source_field_options = !empty($form['type_configuration'][$plugin->getPluginId()]['source_field']['#options']);
+      $form['type_configuration'][$plugin->getPluginId()]['create_source_field'] = [
+        '#type' => 'checkbox',
+        '#title' => $this->t('Create source field automatically when saving this form.'),
+        '#description' => $this->t('If checked, a default field will be created and used as a source field. You can change this setting later on.'),
+        '#default_value' => $bundle->getCreateSourceField(),
+        // Try to place this checkbox close to the sourcefield select element.
+        '#weight' => !empty($form['type_configuration'][$plugin->getPluginId()]['source_field']['#weight']) ? $form['type_configuration'][$plugin->getPluginId()]['source_field']['#weight'] + 0.01 : -2,
+        '#access' => !$has_source_field_options,
+      ];
+      // If there are no options, the dropdown is meaningless.
+      $form['type_configuration'][$plugin->getPluginId()]['source_field']['#access'] = $has_source_field_options;
+    }
+
     // Field mapping configuration.
     $form['field_mapping'] = [
       '#type' => 'fieldset',
@@ -313,6 +329,14 @@ class MediaBundleForm extends EntityForm {
     $plugin_configuration = !empty($this->configurableInstances[$plugin]['plugin_config']) ? $this->configurableInstances[$plugin]['plugin_config'] : [];
     $instance = $this->mediaTypeManager->createInstance($plugin, $plugin_configuration);
     $instance->submitConfigurationForm($form, $form_state);
+
+    // Save the flag to auto-create a source field.
+    $this->entity->create_source_field = $form_state->getValue([
+      'type_configuration',
+      $plugin,
+      'create_source_field',
+    ]);
+
   }
 
   /**
diff --git a/src/MediaBundleInterface.php b/src/MediaBundleInterface.php
index 97e02f9..6bc850a 100644
--- a/src/MediaBundleInterface.php
+++ b/src/MediaBundleInterface.php
@@ -89,6 +89,14 @@ interface MediaBundleInterface extends ConfigEntityInterface, RevisionableEntity
   public function getStatus();
 
   /**
+   * Returns the flag that indicate if a source field should be auto-created.
+   *
+   * @return bool
+   *   TRUE if the field should be created when saving the bundle.
+   */
+  public function getCreateSourceField();
+
+  /**
    * Sets whether a new revision should be created by default.
    *
    * @param bool $new_revision
diff --git a/src/MediaTypeBase.php b/src/MediaTypeBase.php
index a472e7d..0041851 100644
--- a/src/MediaTypeBase.php
+++ b/src/MediaTypeBase.php
@@ -3,14 +3,14 @@
 namespace Drupal\media_entity;
 
 use Drupal\Component\Plugin\PluginBase;
+use Drupal\Component\Utility\NestedArray;
 use Drupal\Core\Config\Config;
 use Drupal\Core\Entity\EntityFieldManagerInterface;
 use Drupal\Core\Entity\EntityTypeManagerInterface;
-use Drupal\Core\StringTranslation\StringTranslationTrait;
+use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
-use Drupal\Component\Utility\NestedArray;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
 use Symfony\Component\DependencyInjection\ContainerInterface;
-use Drupal\Core\Form\FormStateInterface;
 
 /**
  * Base implementation of media type plugin.
@@ -158,4 +158,11 @@ abstract class MediaTypeBase extends PluginBase implements MediaTypeInterface, C
     return 'media:' . $media->bundle() . ':' . $media->uuid();
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function getDefaultSourceField() {
+    return [];
+  }
+
 }
diff --git a/src/MediaTypeInterface.php b/src/MediaTypeInterface.php
index 2a171c2..9e84257 100644
--- a/src/MediaTypeInterface.php
+++ b/src/MediaTypeInterface.php
@@ -2,8 +2,8 @@
 
 namespace Drupal\media_entity;
 
-use Drupal\Component\Plugin\PluginInspectionInterface;
 use Drupal\Component\Plugin\ConfigurablePluginInterface;
+use Drupal\Component\Plugin\PluginInspectionInterface;
 use Drupal\Core\Plugin\PluginFormInterface;
 
 /**
@@ -85,4 +85,26 @@ interface MediaTypeInterface extends PluginInspectionInterface, ConfigurablePlug
    */
   public function getDefaultName(MediaInterface $media);
 
+  /**
+   * Provide a default source field.
+   *
+   * Plugins defining media bundles are suggested to implement this method and
+   * create a field that will be used as default source field, on bundle
+   * creation. Make sure this method returns unsaved entities, once these are
+   * only going to be saved and used if the user marked the option to use the
+   * default field provided.
+   *
+   * @return array
+   *   An associative array containing the following keys:
+   *   'config' => \Drupal\field\Entity\FieldStorageConfig A config entity for
+   *   this field storage.
+   *   'field_name' => (string) The name to be used for the field instance.
+   *   'label' => (string) The label to be used for the field instance.
+   *   'field_widget' => (string) The id of the widget to use.
+   *   'field_formatter' => (string) The id of the formatter to use.
+   *   Note that the storage config entity need to be returned unsaved, and the
+   *   main form will be responsible for saving them.
+   */
+  public function getDefaultSourceField();
+
 }