php artisan make:mail ConfirmPayment --markdown="emails.confirm-payment"

//sending via tinker
Mail::to($pilot = App\Pilot::first())->send(new App\Mail\ConfirmPayment($pilot));

// ConfirmPayment
public $pilot;

public function __construct($pilot)
{
    $this->pilot = $pilot;
}

// 1.Customizing the email template
php artisan vendor:publish --tag=laravel-mail

// will publish files in views/mail/html/themes
// 2.duplicate the .css inside themes an rename it

// 3.go to config/mail.php and change the 'markdown' theme to renamed file above (.css)

//4. to update the changes before testing:
php artisan config:cache