Any idea on how to include a an option in display handler in views I want to include a check box below pager options i achieved it with form alter  . The problem is how can i retrieve or store the value which user has selected and use that value for further process in views
Since you want to add the configuration of the display (which is a plugin), you have two options:


Create a new display plugin
Change the class of the existing page plugin.


The two options are essentially the same, in the sense that you need to create a custom plugin class for views display. The only difference is if you alter what the plugin manager has stored or if you define a new one.

You should extend the existing \Drupal\views\Plugin\views\display\Page class.

Most of the stuff, you don't need to worry about, but you need to extend the following methods:


defineOptions
buildOptionsForm
submitOptionsForm


A very simple implementation of a new plugin class (totally untested code, but should work with small alterations)

use Drupal\views\Plugin\views\display\Page

/**
 * Custom page display to add more options.
 *
 * @ViewsDisplay(
 *   id = "custom_page",
 *   title = @Translation("Custom Page"),
 *   help = @Translation("Display the view as a page, with a URL and menu links."),
 *   uses_menu_links = TRUE,
 *   uses_route = TRUE,
 *   contextual_links_locations = {"page"},
 *   theme = "views_view",
 *   admin = @Translation("Custom Page")
 * )
 */
class CustomPage extends Page {

  /**
   * {@inheritdoc}
   */
  protected function defineOptions() {
    $options = parent::defineOptions();
    $options['custom'] = [
      'contains' =&gt; [
        'checkbox' =&gt; ['default' =&gt; FALSE],
      ],
    ];
    return $options;
  }

  /**
   * {@inheritdoc}
   */
  public function buildOptionsForm(&amp;$form, FormStateInterface $form_state) {
    parent::buildOptionsForm($form, $form_state);
    // A bit tricky, since views uses a concept of sections. Either you need 
    // to define your own section or you can just add your config to an existing
    // section. If you use an existing it will be a lot easier.
  }


 /**
   * {@inheritdoc}
   */
  public function submitOptionsForm(&amp;$form, FormStateInterface $form_state) {
    parent::submitOptionsForm($form, $form_state);

    switch ($form_state-&gt;get('section')) {
      case '?':
        $values = $form_state-&gt;getValue('?');
        $this-&gt;setOption('custom', $values);
        break;
    }
  }
}