code: public function actionCreate()
      {
          /** @var User $user */
          $user = \Yii::createObject([
              'class'    => User::className(),
              'scenario' => 'create',
          ]);
  
          $this->performAjaxValidation($user);
  
          if ($user->load(\Yii::$app->request->post()) && $user->create()) {
              \Yii::$app->getSession()->setFlash('success', \Yii::t('user', 'User has been created'));
              return $this->redirect(['index']);
          }
  
          return $this->render('create', [
              'user' => $user
          ]);
      }
docs: Creates a new User model.
  If creation is successful, the browser will be redirected to the 'index' page.
  @return mixed