'textfield', '#title' => $this->t('Your favorite animal.') ]; $form['submit_animal'] = [ '#type' => 'submit', '#value' => $this->t('Submit your chosen animal'), ]; return $form; } /** * {@inheritdoc} */ public function submitForm(array &$form, FormStateInterface $form_state) { drupal_set_message($this->t('Your favorite animal is: @favorite_animal', ['@favorite_animal' => $form['favorite_animal']['#value']])); } }