Is there a way to retrieve a job app that has been deleted?

Are you referring to a deleted form or a deleted submission?

If you accidentally deleted a form, you can restore it from the Trash folder. Here's a guide: https://www.jotform.com/help/134-How-to-Restore-Deleted-Forms.

Unfortunately, if you deleted a form submission, you cannot retrieve it anymore. If you want, you can check your email for the notification that was sent when the form was submitted by the user.

Hope that helps. Thank you.