Biometric unlock (fingerprint or face) is quick and secure for everyday use. A PIN or passcode is still the backup, and it matters more than most people think.

Android

1. Open Settings, then Security or Security and privacy, then Fingerprint or Face unlock.
2. Follow the steps to add a finger or scan your face.
3. Keep a PIN or password as the fallback. Avoid a pattern that is easy to see on the screen.

iPhone

1. Open Settings, then Face ID & Passcode or Touch ID & Passcode.
2. Turn on iPhone Unlock and any apps you want protected.
3. Use a six-digit passcode rather than a four-digit one.

Mistakes to avoid

• Showing full message previews on the lock screen. Look for Show previews and set it to When unlocked.
• Using a weak PIN such as your birth year.
• Letting someone else add their fingerprint or face to your phone.

If the phone is taken

Biometrics help, but they do not stop someone who knows your passcode. Keep the passcode private, and see how to find a lost phone to lock or erase it remotely.