// config/app.php
'providers' => [
    ...
    NotificationChannels\Lob\LobServiceProvider::class,
],

// config/services.php
...
'lob' => [
    'api_key' => env('LOB_API_KEY'),
],
...

use NotificationChannels\Lob\LobChannel;
use NotificationChannels\Lob\LobPostcard;
use NotificationChannels\Lob\LobAddress;
use Illuminate\Notifications\Notification;

class AccountApproved extends Notification
{
    public function via($notifiable)
    {
        return [LobChannel::class];
    }

    public function toLobPostcard($notifiable)
    {
        return LobPostcard::create()
            ->toAddress(
                LobAddress::create('300 BOYLSTON AVE E')
                    ->name('John Smith')
                    ->city('SEATTLE')
                    ->state('WA')
                    ->zip('98002');
            )
            ->front('https://path.to/my/image/postcardfront.png')
            ->message('Wishing you a wonderful weekend!');
    }
}