How do setup payment on the form?

How do I set it up

Do you mean to setup an order form by using one of the payment methods for receiving payments from your users? If so, please refer to the guide below that can help you with setting the payment method on the form.

https://www.jotform.com/help/165-Setting-Up-Your-First-Order-Form

Also, please go through the guide https://www.jotform.com/help/323-Mastering-Payment-Form-Integrations-with-JotForm for more information on payment integrations. 

Let us know if you need any further assistance. We will be happy to help.