How do I turn on hidden settings on Android?

To turn this feature on, swipe down from the status bar to access your Quick Settings panel then hold down the Settings gear icon in the top-right corner. If executed correctly, your Android phone will vibrate and a message will appear saying that you’ve successfully added the System UI Tuner to your Settings.

Where is the hidden menu on Android?

Tap the hidden menu entry and then below you’ll see a list of all hidden menus on your phone. From here you can access any one of them.