Что такое Notifications?

class OrderShipped extends Notification {
    public function via(User $notifiable): array {
        return ['mail', 'database', 'slack'];
    }

    public function toMail(User $notifiable): MailMessage {
        return (new MailMessage)
            ->subject('Order Shipped')
            ->line('Your order has been shipped.');
    }

    public function toDatabase(User $notifiable): array {
        return ['order_id' => $this->order->id, 'status' => 'shipped'];
    }
}

$user->notify(new OrderShipped($order));
Notification::send($users, new OrderShipped($order));

Каналы: mail, database, broadcast, Slack, SMS (Vonage), push и custom.