How to enable Ckeditor for email templates?
I recently had the same issue and was able to accomplish this through a hook_form_FORM_ID_form_alter(); in a custom module.

&lt;?php 

function MYMODULE_form_webform_email_edit_form_alter(&amp;$form, &amp;$form_state) {
  // This check will determine whether the form already has a ckeditor textarea on it, if not it will initialize ckeditor requirements.
  if (!function_exists('ckeditor_load_by_field')) {
    module_load_include('inc', 'ckeditor', 'includes/ckeditor.lib');
    $input_formats = ckeditor_profiles_compile();
    drupal_add_js(array('ckeditor' =&gt; array('input_formats' =&gt; $input_formats, 'plugins' =&gt; array())), 'setting');
  }

  // Set some vars.  Modify these as needed.
  $format_key = 'full_html'; 
  $element = $form['template']['template'];
  $element_id = 'edit-template--2';

  // The format array here is used within the ckeditor_load_by_field() function, without it things won't work.
  $format = array(
    '#options' =&gt; array(
      $format_key =&gt; $format_key,
    ),
    '#value' =&gt; $format_key,
  );

  // Both of the following keys are required for the textarea to become ckeditor-ified
  $element['#wysiwyg'] = TRUE;
  $element['#id'] = $element_id;

  // Run the ckeditor_load_by_field function which does all the magic.  Modify to match the $element var set above.
  $form['template']['template'] = ckeditor_load_by_field($element, $format);
}