The best place to start if you need help with a specific product is to contact the developer. All WHMCS Marketplace developers have both a website and support URL listed.
A complete PayPal Gateway with additional features that aren’t included in a standard PayPal Gateway!
This module provides support for the Stripe payment gateway for use with WHMCS.
Transfer the paypal fees to your customer
Our WHMCS PayPal Billing Gateway allows you to charge your customer’s PayPal accounts at any time – for any amount, just like they have a credit card on file with you!
Enable "Amazon Pay and Login with Amazon" in WHMCS for single and recurring payments.