Set up face unlock if you want to unlock HTC Desire 820 using the front camera.
1. Go to Settings, and then tap Security.
2. Tap Screen lock> Face Unlock.
3. Tap Set it up and follow the onscreen instructions.
4. Choose a backup unlock method to use in case the phone doesn't recognize
you.
5. Tap Lock phone after, and then specify the idle time before the screen is locked.

To help make face unlock more reliable and more secure, you can:
- Tap Improve face matching to train HTC Desire 820 to recognize your face in
different situations, such as when you're wearing glasses or sporting a beard.
- Select the Liveness check option and you will be asked to blink to unlock the
screen.

Bypassing the lock screen
If you've set a screen lock for HTC Desire 820, you can just skip the lock screen and
go straight to the security screen for unlocking HTC Desire 820.
1. Go to Settings, and then tap Security.
2. Select the Bypass lock screen on wake option.