How to render a form in custom template?

I'm looking to add a form inside a custom template. The form, if I open the path registered inside the file cmodule.routing.yml, works but if i try to use it inside a custom template it doesn't work: with a dump(form) or dump(form.anyfield) i get NULL.

cmodule.routing.yml:

cmodule.manageform: path: '/cmodule/manageform' defaults: _title: 'Documents' _form: '\Drupal\cmodule\Forms\RequestForm' requirements: _permission: 'access content' cmodule.manage: path: '/cmodule/manage' defaults: _controller: '\Drupal\cmodule\Controller\CmoduleController::manageAction' _title: 'Custom Documents' requirements: _permission: 'access content' 

RequestForm.php:

/** * {@inheritdoc} * */ public function buildForm(array $form, FormStateInterface $form_state) { $form['type'] = array( '#type' => 'radios', '#options' => array( '0' =>t('DOC'), '1' =>t('PDF') ), ); $form['pid'] = array( '#type' => 'textfield', '#title' => t('ID:'), '#required' => FALSE ); $form['submit'] = array( '#type' => 'submit', '#value' => $this->t('Submit'), '#attributes'=> ['class'=>['glyphicon', 'glyphicon-search']], ); return $form; } 

cmodule.module:

/** * Implements hook_theme(). */ function cmodule_theme(){ $templates = array( 'manage_cmodule_page' => array( 'variables' => [ 'id' => NULL, 'form' => NULL ], 'template' =>'manage_cmodule', 'render element' => 'form' ) ); return $templates; } 

the controller contains:

public function manageAction() { $id = 1; $form = \Drupal::formBuilder()->getForm('Drupal\cmodule\Forms\RequestForm'); $form['type']['#title_display'] = 'invisible'; return [ '#theme' => 'manage_cmodule_page', '#form' => $form, '#id' => $id, ]; } 

and then the template/view (contains):

<div> {{ form.form_token }} {{ form.form_build_id }} {{ form.form_id }} {{form.type}} {{form.submit}} </div> etc.. 

But as I said above the template doesn't show the form, but show (if i print it) the #id value passed through the controller. Do you have any suggestions?!

---

UPDATE #1 I tried also to follow the suggestion of Beebee, and then this and this so the code is:

controller:

controller contains: public function manageAction() { $form = \Drupal::formBuilder()->getForm('Drupal\cmodule\Forms\RequestForm'); $render['#form'] = $form; $render['theme'] = 'manage_cmodule_page'; return $render;; } 

and the implementation of hook_theme in .module file is:

return [ 'manage_cmodule_page' => [ 'template' =>'manage_cmodule', 'render element' => 'form', ] ]; 

The result is an empty page with an error inside the apache log:

[php7:error] [pid 12660:tid 1592] [client ::1:59521] PHP Fatal error: Out of memory (allocated 270532608) (tried to allocate 266354688 bytes) in C:\drupal\vendor\twig\twig\lib\Twig\Extension\Debug.php on line 60, referer: http://localhost/drupal/

if I remove the following row from the controller

$render['theme'] = 'manage_atps_page'; 

the page loads, but it is empty (without any form).

UPDATE #2

I fixed my issue following also the idea of Alex Kuzava. Thus I used the code of UPDATE 1, with the new directory of the form, and then I added these 3 lines inside the part of my template (otherwise the submit button doesn't work).

{{ form.form.form_build_id }} {{ form.form.form_id }} {{ form.form.form_token }}