We added in our last release the ability to customize the thank you message on custom form submission at the category level (so that all custom forms in that category would get your custom message without having to edit each one). In our next week release (3/24) we will also be giving you the ability then to create a custom thank you message at the form level as well so that it would overwrite the category level message. We will also be giving you the ability in the same release to add head and body tracking snippets to your confirmation so that if you use website tracking like Google Analytics you can track where submission traffic is coming from.

So sorry all! I had my school forms hat on when I replied. But the good news is now I'll have to make good on this one - I've got it pulled into our dev planning so hopefully you'll be seeing ability to customize the confirmation on custom forms soon. Stay tuned.

This exists - when you save and edit the form (or go into settings afterward), if you click on confirmation you'll get the editor for the confirmation page that it redirects to on submit.