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.
The link is generated by PayPal and it is not possible to get this link, save it and go back to complete the payment in another time since this is temporary available and may be that when you try to load the payment link it is not available anymore.
Once you have completed the payment manually your submitter will need to submit the form again or pay you directly, here is a link with more info about incomplete payments on PayPal: Paypal-Incomplete-Payments-FAQ
I would suggest you to enable IPN on your PayPal account as well, here is a guide about that: -How-to-Enable-IPN-for-Paypal