Staying on forms for just a bit longer, let's quickly learn how to render forms programmatically. Also, we have already seen how to map a form to a route definition so that the page being built contains the form when accessing the route path. However, there are times where we need to render a form programmatically, either inside a Controller or a block or wherever you want. We can do this using the FormBuilder service.
The form builder can be injected using the form_builder service key or used statically via the shorthand:
$builder = \Drupal::formBuilder();
Once we have it, we can build a form, like so:
$form = $builder->getForm('Drupal\hello_world\Form\SalutationConfigurationForm');
In the preceding code, $form will be a ...