How to turn "Ok Google" on or off

If you turn off "Ok Google", you can still talk with your Assistant by touching and holding the on-screen Home button on your Device 

1. On your tablet, touch and hold the on-screen Home button.
2. At the top-right, tap  More   Settings.
3. Under "Devices", select your tablet.
4. Turn on Google Assistant  turn “Ok Google” detection on or off.
   • If you don’t see these steps, you’re using an earlier version of the Google app. Instead, tap "Ok Google" detection  turn Say "Ok Google" any time on or off.