Should you need to leave an iPad unattended in a kiosk stand (or similar) you don't want people to be able to access all of the app functionality. This is where Kiosk Mode comes in handy.
Aside from entering the app in to Kiosk Mode, you may also wish to lock the device itself so that the home button is deactivated too, to enter your device into this mode follow these steps;
How to enable Guided Access on iPhone and iPad
Launch the Settings app on your iPhone or iPad.
Tap on General.
Tap on Accessibility.
Tap on Guided Access under the Learning section.
Tap the switch to turn on Guided Access.
Tap on Passcode Settings.
Tap Set Guided Access Passcode and set a passcode.