If you use WordPress & WHMCS, then WHMCS Cart & Order Pages (WCOP), WordPress can be your best choice.
It offers different styles for order pages, including its famous one-page checkout.
The One Page Checkout optimizes the checkout process for your WHMCS store to be simple and responsive for users on any devices. By reducing the steps needed to submit an order, customers are more likely to complete the process and thereby increase your online profits and conversion rate.
One Page Checkout template of WCOP is optimized to show all steps needed to complete the order.