Display custom form mode in twig with drupal_entity_form
You need to create a custom module
Let say you call it module_name
In your module_name.module file you'll have to use the hook_entity_type_build()
/**
 * Implements hook_entity_type_build().
 */
function module_name_entity_type_build(array &amp;$entity_types) {
  $entity_types['node']-&gt;setFormClass('applicant', 'Drupal\node\NodeForm');
}

Then enable your module_name module and flush the cache.