The passcode is the 4 digit key that you are asked to enter when you exit test mode, or re-enter the BetterMind app. The passcode is specific to your iPad.
The password can either be letters or numbers, and is entered when you signed up your user account with BetterMind. The password is required to login to BetterMind if you have logged out. The password is not specific to your iPad. The passcode and password may be the same or different.