Add a personalized presentation to an entity (view mode)

/**
 * Implements hook_entity_info_alter().
 */
function my_module_entity_info_alter(&$entity_info) {
  // Add new view mode to user entity.
  $entity_info['user']['view modes']['example'] = array(
    'label' => t('Example view mode for user entity'),
    'custom settings' => TRUE,
  );
}

You can also alter the presentation (view mode) of an entity in it visualization.  I teach you how to do it in this snippet.