Smart Lock automatically unlocks the device when trusted locations (work, home) or other devices (Bluetooth® headset, NFC tag) have been detected.
Navigate: Apps icon > Settings > Screen Lock.
When prompted, enter Gmail password and tap or click Confirm.
Next to Smart Lock, tap Setup.
Tap or click Find your phone.
Your Smart Lock capable Android smartphone must be within Bluetooth range and powered on.
Enter the current unlock method (e.g., PIN, pattern, etc.).
Select any of the following available options then follow the onscreen prompts to set up a trusted unlock:
For more info on Smart Lock (editing, removing settings, etc.), refer to the Google support page.
Set Bluetooth or NFC devices to keep your phone unlocked when that device is connected.
Set locations (home, work, etc.) to keep your phone unlocked whenever you're there.