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.
As far as I know, you can NOT embed the custom embed code of paypal button into JotForm form. The script codes that are on the paypal button code will only be erased by the form when save in the form builder.
However, we highly recommend that you just use the form Paypal integration instead, which have the same purpose.
Review this guide http://www.jotform.com/help/50-PayPal-Forms
This way, each user will be redirected to the PayPal payment page upon submitting the form, and each successful payment will be moved into form Submissions.
Please feel free to contact us if you need any further assistance.