LG L51AL Guia Del Usuario página 40

Smart Lock
You can use Smart Lock to make unlocking your device easier. You can set
it to keep your device unlocked when you have a trusted Bluetooth® device
connected to it, when it's in a familiar location like your home or work,
when it recognizes your face or voice, or when it detects it's on your body.
Setting up Smart Lock feature
1 Tap >
2 Before you add any trusted devices, trusted places, trusted face, trusted
voice, or on-body detection, you need to set up a screen lock (Knock
Code, Pattern, PIN or Password).
Basics
> > Lock screen > Smart Lock.
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