title: webform alter drupal 8
body: <p>i'm new on drupal 8 and i want to try to custom the basic template of the webform module with my own template in TWIG , SASS.
  I know i have to create a custom module but after read the drupal documentation , i don't know how i can do it correctly.
  Any one can help me ?
  i try to create a module with this code</p>
  <pre><code>function webform_example_form_alter(&amp;$form, &amp;$form_state, $id) {
    if ($id == 'webform_submission_contact_form') {
      $form['elements']['name']['#title'] = t('Name');
    }
  }
  </code></pre>