View form alter drupal

 /**
 * Implements hook_form_FORM_ID_alter().
 */
function register_form_views_exposed_form_alter(array &$form, FormStateInterface $form_state, $form_id) {
  //You need to verify the id
  if ($form['#id'] =='views-exposed-form-search--page-1') {
       // print_r($form);
      //Setting placeholder
       $form['keys']['#prefix']= '<div class="icon"><i class="fa fa-search" aria-hidden="true"></i>';
       $form['keys']['#attributes']['placeholder'] = t('Search for Topics');
       $form['keys']['#attributes']['class'][] = 'forum_spec_search';
      unset($form['keys']['label']);
        $form['keys']['#sufix']= '</div>';
    
  }
}