Smart Lock feature helps you to turn off the automatic lock screen and keeps your phone unlocked when the device is safe with you. If you set-up and enable this feature, you won't need to enter your PIN, pattern or password to unlock when your device is in your pocket.
Note: This feature could be different depends on the model and Android version. Below you can find the instructions for ZB555KL with Android 8.0
How to turn on Smart Lock:
1. Swipe down on the home page and open the Settings
2. Go to Security&Lock screen > Smart Lock
3. Enter your current PIN, password or pattern to continue.
4. Four Smart Lock options are available. For On-body detection, it keeps your device unlocked when its in the users' position (e.g. in the pocket, held in hand)
For the other features, follow the steps on display to set up your Smart Lock options.
Note: If you don't use the device in 4 hours or you reboot device, you will need to enter the password by yourself.