Kiosk mode sets a form up for a device that several people share, one after another. An iPad on a table at an event, a laptop at a front desk, a screen in a studio lobby.
Without it, whoever submits first leaves the success screen sitting there, and the next person has to know to start over. With it, the success screen counts down and the form clears itself, blank and ready. Kiosk mode is available on the Business and Premium plans.

Automatic reload time (seconds) is how long uploaders see the success screen before the form clears. It starts at 5 seconds, the shortest you can set is 1, and there is no upper limit.
Five seconds is enough for someone to read a short confirmation and step away. Give it longer if your success message asks them to do something, like take a paper form from the table or check in with someone.
Kiosk success message is the line at the bottom of the success screen. Type {seconds} wherever you want the number to appear and it counts down in place, once a second, until the form clears.
The default is "This form will automatically reload in {seconds} seconds."
They get the normal success screen first: the confirmation icon, your Success header and Success text, and a line counting the files they sent and their total size. Your kiosk message sits below all of that, under a divider, with the countdown running.
When the countdown reaches zero, the form comes back empty. Every field is cleared and the files from the last submission are gone from the screen, so the next person never sees what the person before them typed.

A form can clear itself or send uploaders to a page of your own, not both. Turning on either one while the other is on asks you to confirm, and confirming turns the other off. With kiosk mode on, the redirect setting reads "Disabled while Kiosk mode is on". Turning kiosk mode on this way also clears the address you had saved, so enter it again if you go back to using a redirect. See Redirect uploaders after submission.