What is JotForm?
JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
At JotForm, we want to make sure that you’re getting the online form builder help that you need. Our friendly customer support team is available 24/7.
We believe that if one user has a question, there could be more users who may have the same question. This is why many of our support forum threads are public and available to be searched and viewed. If you’d like help immediately, feel free to search for a similar question, or submit your question or concern.
You can only add one payment method on a form.
To remove or change the current one you have, first you need to delete the existing one, after that a message will pop-up showing if you would like keep the products, you can then add the Paypal integration to your form after that. Here's a screencast on how to do it:
You can also refer to the following guides to help you setup your order form:
If you are setting up multiple payment methods, you can follow this guide: http://www.jotform.com/help/182-How-to-Create-a-Basic-Multiple-Payment-form
I hope that helps.