Drupal 8 How to modify Email Max length to 320 Characters


You can using hook_element_info_alter.

mymodule.module

/*
 * Implements hook_element_info_alter().
 */
function mymodule_element_info_alter(array &$info) {
  if (!empty($info('email'))) {
    $info('email')('#maxlength') = 320;
  }
}

Flush all caches so hook gets pickedup.