How to send an email to admin when new users sign up.

AdminNewUser.php

<?php

namespace App\Mail;

use App\Models\User;
use Illuminate\Bus\Queueable;
use Illuminate\Mail\Mailable;
use Illuminate\Queue\SerializesModels;

class AdminNewUser extends Mailable
{
    use Queueable, SerializesModels;

    /**
     * @var User
     */
    private $user;

    /**
     * Create a new message instance.
     *
     * @return void
     */
    public function __construct(User $user)
    {
        $this->user = $user;
    }

    /**
     * Build the message.
     *
     * @return $this
     */
    public function build()
    {
        return $this->subject('New User')
            ->markdown('mail.new-user', [
                'user' => $this->user
            ]);
    }
}

AdminNewUserListener.php

<?php

namespace App\Listeners;

use Illuminate\Auth\Events\Registered;
use App\Mail\AdminNewUser;
use Illuminate\Support\Facades\Mail;

class AdminNewUserListener
{
    /**
     * Handle the event.
     *
     * @param  Registered  $event
     * @return void
     */
    public function handle(Registered $event)
    {
        Mail::to(config('mail.from.address'))->send(new AdminNewUser($event->user));
    }
}

EventServiceProdiver.php

<?php

namespace App\Providers;

use App\Listeners\NewUser;
use Illuminate\Support\Facades\Event;
use Illuminate\Foundation\Support\Providers\EventServiceProvider as ServiceProvider;
use Illuminate\Auth\Events\Registered;

class EventServiceProvider extends ServiceProvider
{
    /**
     * The event listener mappings for the application.
     *
     * @var array
     */
    protected $listen = [
        Registered::class => [
            SendEmailVerificationNotification::class,
            NewUser::class
        ],
    ];

    /**
     * Register any events for your application.
     *
     * @return void
     */
    public function boot()
    {
        parent::boot();

        //
    }
}

new-user.blade.php

@component('mail::message')
# New User

A new user with email {{ $user->email }} has registered to your site.
@endcomponent