Randomly display questions in Webform - to use as an exam
You can use form alter to access $form array and display/hide specific elements, more details: https://www.drupal.org/docs/8/modules/webform/webform-cookbook/how-to-programmatically-hide-and-show-webform-elements. 

function CUSTOM_MODULE_form_webform_submission_WEBFORM_NAME_add_form_alter(array &amp;$form, FormStateInterface $form_state, $form_id) {
  $elements = &amp;Drupal\webform\Utility\WebformFormHelper::flattenElements($form['elements']);

  $elements['question_one']['#access'] = FALSE;
  $elements['question_two']['#access'] = FALSE;
}