Stop being concerned about your friends and family snooping through your data if you hand them your iPhone. Guided Access limits what they can do on your personal device.
How to set up Guided Access
Go to Settings > Accessibility, then turn on Guided Access.
Tap Passcode Settings, then tap Set Guided Access Passcode.
Enter a passcode, then re-enter it. From here, you can also turn on Face ID or Touch ID as a way to end a Guided Access session.
Start a Guided Access session
Open the app that you want.
On an iPhone X or later, triple-click the side button. On an iPhone 8 or earler, triple-click the Home button.
If you want parts of your screen to stop responding to touch, use one finger to circle those areas. You can move or resize the circle, or tap the X to remove it.
Tap Guided Access, then tap Start.
Or to start a Guided Access session with Siri*, open the app that you want, then tell Siri "Turn on Guided Access."
Control which features are available
To turn off features or set a time limit, triple-click the Side or Home button, then tap Options. If you don't see Options, triple-click the Side or Home button again and enter your passcode.
Turn on the options that you want, then tap Done.
End a Guided Access session
Triple-click the Side or Home button, enter your Guided Access passcode, then tap End. Or if you turned on Touch ID or Face ID for Guided Access, double-click the Side or Home button.
For additional information: https://support.apple.com/en-us/HT202612