Run php artisan vendor:publish.
This will create vendor/cashier/receipt.blade.php file in your views folder, which you can modify as per your requirement & commit.

1. Extend Cashier's Invoice - Laravel\Cashier\Invoice.
2. Add $options->setIsRemoteEnabled(true); to pdf method:

public function pdf(array $data)
{
    if (! defined('DOMPDF_ENABLE_AUTOLOAD')) {
        define('DOMPDF_ENABLE_AUTOLOAD', false);
    }

    $options = new Options;
    $options->setChroot(base_path());
    $options->setIsRemoteEnabled(true);

    $dompdf = new Dompdf($options);
    $dompdf->setPaper(config('cashier.paper', 'letter'));
    $dompdf->loadHtml($this->view($data)->render());
    $dompdf->render();

    return $dompdf->output();
}