JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
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.
If you would like to direct your user to any payment gateway such as Paypal after they click submit button, you can use one of our payment wizard. They works as you wish. You can reach payment wizard that supported by JotForm on Payment Field at Form Builder.
On the other hand, If your user close the payment window or if the transaction does not be made because of any reason, your form would still be submitted but they would be queued as Incomplete payment.
I attached here related guidances and suggest you to have a look them for more information.
If you have more questions, please do not hesitate to contact us. We would be pleased to assist you.