Androidĭark mode on Android, or dark theme as Google likes to call it, automatically switches the colours for nearly every Google-owned app. You can also tap the toggle underneath to set dark mode to come on automatically - simply go on ‘Options’ after turning it to automatic to choose when dark mode comes on, either sunset to sunrise every day or at times of your choosing.
Tap ‘Display & Brightness’ and tap either ‘Light’ or ‘Dark’ to choose which appearance you want. A more conventional way to switch to dark mode on iOS is to go to settings.