Notificação de acordo com o cadastro do usuário

WelcomeUserNotification.php

<?php

/**
 * Get the notification's delivery channels.
 *
 * @param  mixed  $notifiable
 * @return array
 */
public function via($notifiable)
{
    return $notifiable->use_fallback_mail ? [FallbackMailChannel::class] : ['mail'];
}