Dark mode on Google is available on the Google app for Android and iOS, as well as on the Google Chrome web browser for desktop. To turn dark mode on or off in the Google app, tap More > Settings > Theme. On Chrome for desktop, go to More > Settings > Appearance. Under "Themes," you can select "Dark" to turn dark mode on or "Default" to turn it off. You can also schedule dark mode to turn on and off automatically based on the time of day.