How to alter a Webform's settings before rendering a submission form

This recipe shows how to dynamically alter a Webform's settings before rendering a submission form.

The below example demonstrates how to disable a Webform's preview button and tab when editing a submission.

use \Drupal\Core\Form\FormStateInterface;
use \Drupal\webform\WebformSubmissionInterface;

/**
 * Implements hook_ENTITY_TYPE_prepare_form().
 */
function webform_webform_submission_prepare_form(WebformSubmissionInterface $webform_submission, $operation, FormStateInterface $form_state) {

  // Only execute the below code if we are editing a submission.
  if ($operation != 'edit') {
    return;
  }

  // Get the submission's Webform.
  $webform = $webform_submission->getWebform();

  // Only disable the preview for the 'example_wizard' webform included 
  // in the webform_example.module.
  if ($webform->id() == 'example_wizard') {
    $webform->setSetting('preview', DRUPAL_DISABLED);
  }
}