WHMCS includes a large number of apps and integrations that we ship with WHMCS by default, and you can find more apps and integrations from the WHMCS Marketplace.
Email verification ensures that a client's registered email address is valid after client creation or changes to the email address.
Configurable Options allow clients to select options to customize your products.
The Contacts tab in the Client Profile lets you add, view, and manage client contacts, allowing email messages to go to additional recipients.
Cross-selling allows you to display product recommendations to customers based on their existing services and the contents of their cart.
WHMCS can automatically run fraud protection checks on orders to help ensure only valid clients get through and to block any potential fraud.
The system uses your Automation Settings configuration to determine when to generate invoices for your customers and how to format them.