App Inventor is a browser-based tool for building Android apps without coding. It uses a block-based, visual programming language that allows anyone to create apps. While it is simple for beginners to use, apps developed in App Inventor have limitations compared to standard Android development like access to hardware buttons and limited debugging. It is best for single screen apps with low functionality for personal or educational use as an introduction to app development. The process of creating an app in App Inventor involves registering an account, downloading software, dragging and dropping UI elements, adding blocks for functionality, and testing the compiled app.