A free app for Android, by Tyler Nijmeh.
Immersive - Low-Level Immersive Mode is a tool that allows you to use your Android phone in a low-level, full-screen mode. In other words, it lets you use your phone in a way that puts it in a state where it can be used without being displayed on the screen. This is useful for situations where you need to use your phone in a low-level way, such as when you are using a browser or when you are playing a game.
The app has an immersive mode that will hide the status bar and the navigation bar, and it has a reset button to disable the app completely.
You will need to install the app and set it up in order to use it. You can find a detailed guide on how to do that in the app itself.
