Smart Lock automatically unlocks the device when trusted locations (work, home) or other devices (Bluetooth® headset, NFC tag) have been detected.
A secure lock type (PIN, pattern, etc.) must be set up for Smart Lock to be available. Turning off the secure lock also turns off Smart Lock.
From a Home screen, tap the Apps icon > Settings > Security.
If Settings is unavailable, tap the Dropdown menu (located in the upper left) then select Alphabetical. If still unavailable, refer to Manage App Icons.
Tap Smart Lock.
Enter the current unlock method (e.g., PIN, pattern, etc.).
Select any of the following available options then follow the onscreen instructions 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