When handing your device over to someone else, like a young child, you can use Guided Access mode to restrict access to certain buttons. To enable this, open the Settings app, select the General option, then Accessibility. From here choose Guided Access and turn it on. Tap Set Passcode too, so it can’t be turned off too easily.
Then, while using an app, quickly triple-press the Home button to turn on Guided Access Mode. You can then draw around buttons on screen that you don’t want to be enabled before handing over your iPad.
After you get the device back, triple-press the Home button three times, enter the passcode, and select End.