Duplicate the open-source Bank Transfer and Mail In Payment payment gateway modules and use them for creating your own custom modules.
Create a product to offer for sale. Products include many options for configuring pricing, billing, provisioning modules, and more.
Create a product group (a collection of related products that display together). Before you can create products, you must create a product group.
Create a product addon to offer Sitejet Builder. Sitejet Builder allows clients to create professional websites easily without coding.
Create a product addon. Product addons let you offer additional items that the client can select when purchasing the parent product.
Customize the redirect location for your affiliates' links by updating your WHMCS system's domain or by editing the aff.php file.
You can customize any of the emails that your WHMCS installation sends to your customers. WHMCS sends email whenever specific actions occur, and each action has an associated email template that you can customize from within the Admin Area.