If you have an iPhone X or later, or 2018 models of the iPad 11-inch and iPad 12.9-inch, you can use Face ID to secure your device. If you share your device with another person, you can add their face to settings as well.
Alternate Face ID
- Open Settings.
- Go to Face ID & Settings and enter your passcode when asked.
- Tap Set up an Alternate Appearance, then tap Get Started.
- Have your friend hold the iPhone and follow the instructions to move their head around while looking into the front camera.
For extra security, make sure the settings for Require Attention for Face ID and Attention Aware Features are enabled.