form

gistfile1.txt

<?php

  /**
   * {@inheritdoc}
   */
  public function buildForm(array $form, FormStateInterface $form_state) {

    $config = $this->config('googlelogin.settings');

    $url = Url::fromUri('https://console.developers.google.com');
    $text = t('Google project');
    $link = Link::fromTextAndUrl($text, $url);
    $html_link = render ($link->toRenderable());
    
    $form['googlelogin_text'] = array(
      '#type' => 'item',
      '#markup' => '<h4 class="label">' . t('You can create a new project in google in this :link',[':link' => $html_link ]) . '</h4> ',
    );


    $form['googlelogin_id'] = array(
      '#type' => 'textfield',
      '#title' => $this->t('Google customer id'),
      '#default_value' => $config->get('googlelogin.id'),
    );
    $form['googlelogin_secret'] = array(
      '#type' => 'textfield',
      '#title' => $this->t('Google customer secret'),
      '#default_value' => $config->get('googlelogin.secret'),
    );

    return parent::buildForm($form, $form_state);
  }