I am making a check-in and check-out app that I would want to publish on the app store. How would I achieve the check in and check-out functionality if they are no logins?
I think the best way to achieve this without a login is by creating a link which references their row. You could also have them search for their name or an identifier but that wouldn’t be very secure.
You need a database to feed the form if you want to ID the users for check-in.
So for example users will only be able to continue, if the name or Reservation ID they input is also contained in the original database. You can use a LOOKUP formula for this.
Otherwise just create a form for the check-in to mine the data from the user, and then another form for check-out which gets the info from users from the check-in table.