How can someone edit a form they have submitted?

It is possible to make the users to edit their submissions at a later date by sending them a edit link in the auto-responder email.

Please refer to the following guide that helps you in achieving this requirement.

https://www.jotform.com/help/40-How-to-Let-Users-Update-Their-Form-Submissions-at-a-Later-Date

Hope this information helps!