How can I integrate my form with PayPal?

I need help setting up the payment part for customers on my form.

May we know which PayPal integration will you use? 

If you will integrate your form with PayPal Standard, then this guide will help you doing so: https://www.jotform.com/help/391-How-to-Integrate-Form-with-Paypal-Standard- 

With the standard integration your users will be redirected to the PayPal payment page where they can complete the payment. If you would like to allow them to pay either using their credit card directly on the form or using a PayPal account, then you would need to add the PayPal Pro integration, here is the guide: https://www.jotform.com/help/458-How-to-Integrate-Form-with-Paypal-Pro 

You may refer to this guide in order to know how to set up products on your payment integration: https://www.jotform.com/help/165-Setting-Up-Your-First-Order-Form 

Also, if you have any specific requirement or any questions, please let us know, we will be glad to help you.