Save form entries when payment is not made

Is there an option such that if a user fills a form, clicks Submit to pay, and for some reasons an error happens or the user closes the browser, to come back to the form and find the fields of the form populated with the entries he made, so that he just has to click Submit again to pay?

It is possible to use the auto-fill feature. You can see here more details:

https://www.jotform.com/help/227-How-to-Enable-Auto-Fill-Feature 

The Auto-save stands for how often will the system save new versions and the time to live stands for how long will the information be saved on the browser:

As long as the user uses the same equipment/browser and does not clear cache it is possible to have the form filled in.

Let us know if we can assist you further.