They don't make it easy, but we do
How-To: Disable Google Assistant – Android
Google Assistant is always there for you, always listening. Even when you don’t want it to be. Saying “OK Google” and having a digital assistant answer your questions can be incredibly convenient. But what if you want to turn that assistant off?
Whether it’s due to privacy concerns or some other reason, it doesn’t seem all that easy to turn the OK Google feature on or off on your phone. In fact, it doesn’t seem easy to adjust many of the Google Assistant settings.
That's why in this guide we offer you how to enable or disable OK Google at any time, and explain what other useful settings you might want to adjust.