$language = \Drupal::languageManager()->getCurrentLanguage()->getId();
  $user = \Drupal\user\Entity\User::create();
  $user->setPassword($form_state->getValue('pass'));
  $user->enforceIsNew();
  $user->setEmail($form_state->getValue('mail'));
  $user->setUsername($form_state->getValue('name'));//This username must be unique and accept only a-Z,0-9, - _ @ .
  $user->set("init", 'mail');
  $user->set("langcode", $language);
  $user->set("preferred_langcode", $language);
  $user->set("preferred_admin_langcode", $language);
  $user->activate();

  //Save user account
  $user->save();

  // No email verification required; log in user immediately.
  _user_mail_notify('register_no_approval_required', $user);
  user_login_finalize($user);
  drupal_set_message($this->t('Registration successful. You are now logged in.'));
  $form_state->setRedirect('');