code: public function loginAction(Request $request)
      {
          $session = $request->getSession();
  
          $form = $this->createFormBuilder()
              ->add('username', TextType::class, array('label' => 'Username'))
              ->add('password', PasswordType::class, array('label' => 'Password'))
              ->add('rememberMe', CheckboxType::class, array('label' => 'Remember Me', 'required' => false))
              ->getForm();
  
          $helper = $this->get('security.authentication_utils');
          if ($lastUsername = $helper->getLastUsername()) {
              $form->setData(array('username' => $lastUsername));
          }
  
          return array(
              'form' => $form->createView()
          );
      }
docs: Displays a form to login
  
  @Template