debugmail as a default debug transport in config/app.php

app.php

    'EmailTransport' => [
        'default' => [
            'className' => 'Smtp',
            'host' => 'debugmail.io',
            'port' => 25,
            'timeout' => 30,
            'username' => 'YOUR_DEBUGMAIL_EMAIL',
            'password' => 'YOUR_DEBUGMAIL_PROJECT_PASSWORD',
            'client' => null,
            'tls' => null,
            'url' => env('EMAIL_TRANSPORT_DEFAULT_URL', null),
        ],
    ],