web.php

<?php

/*
|--------------------------------------------------------------------------
| Web Routes
|--------------------------------------------------------------------------
|
| Here is where you can register web routes for your application. These
| routes are loaded by the RouteServiceProvider within a group which
| contains the "web" middleware group. Now create something great!
|
*/

$router->get('/notification', function () {
    $notification = new \App\Notifications\InvoicePaid;

    return $notification->toMail('test@example.com');
});