Can you set a form to clear selections on submit so user cant "back page"

please let me know

The form will automatically clear the data so the user can enter new one, but if you use the browser's back button, it's possible that the browser prefills some fields. If your purpose is to allow users to fill out the form again and have a blank form, you may either provide the form URL on the thank you page or redirect them automatically to the blank form. 

This guide will help you setting up the thank you page and including the form URL: https://www.jotform.com/help/211-Setting-up-the-Thank-You-Page

This guide will help you redirecting the user: https://www.jotform.com/help/38-Redirecting-Users-to-a-Different-Page

And this guide will help you getting the form URL: https://www.jotform.com/help/401-Where-to-Find-My-Form-URL

I hope this helps.