How to remove paragraph tag from ckeditor?
In Drupal 8, you may need to implement hook_editor_js_settings_alter and set config.autoParagraph to false, as referenced here: CKEDITOR.config.autoParagraph

/**
 * Implements hook_editor_js_settings_alter().
 */
function MODULE_editor_js_settings_alter(array &amp;$settings) {
  foreach ($settings['editor']['formats'] as $name =&gt; $value) {
    $settings['editor']['formats'][$name]['editorSettings']['autoParagraph'] = FALSE;
  }
}