In config/services.php add:
'ictw' => ['url' => env('ICTW_API_URL'), 'key' => env('ICTW_API_KEY')],

In .env add (real HTTPS URL after deployment):
ICTW_API_URL=https://pay.example.com
ICTW_API_KEY=replace-with-client-secret

Use a POST form with @csrf to route('orders.pay-ictw', $order).
Order must have user_id, status, total fields; adapt names and authorization to your app.
Do NOT mark Paid from a redirect or SMS alone. Status-sync and signed webhooks not implemented.