Can I make a submitted form inactive? So that if someone submitted an application to a program but then withdraws, their form is no longer active?

There are ways to disable the form.

#1. Manually Disable/Enable the Form.

user guide: https://www.jotform.com/help/180-How-to-Enable-Disable-a-Form

#2. Disable the Form using Submission Limits.

user guide: https://www.jotform.com/help/137-How-to-Limit-Submissions-in-a-Form

#3. Prevent end-user re-submitting the form using Unique Submission Limit.

user guide: https://www.jotform.com/help/64-How-to-Set-Unique-Submissions-on-a-Form

Hope this helps. Let us know if you need further assistance.