The information in this guide pertains to the "Register On Checkout" add-on that used to be available for download through the X-Cart App Store, but not any longer. This is a legacy article, no longer supported.
Currently, we can provide this functionality as a custom development service. More information is available here: Register On Checkout.
If you want to be sure that any buyer has a registered profile in your store, use the Register On Checkout add-on.
When installed and enabled, the add-on automatically disables checkout from unauthorized customers and engages them to register at checkout.
Repeat customers will have to sign in with an existing account, while first-time buyers will need to register a new account in your store.