Press the Power button once to turn off the screen
Set a screen lock in Settings
Open Settings
Tap Security or Lock Screen
Choose Screen lock or Lock screen type
Select PIN, password, pattern, Face ID, or fingerprint
Follow the on-screen steps to set it up
Enable auto-lock or screen timeout
Use the Power button to lock the phone anytime
On iPhone, press the Side button to lock the screen
On Android, press the Power button to lock the screen