Physical Keyboard not automatically replacing Onscreen Keyboard on my iPad

Perhaps you providing some information about the keyboard, with which you are having difficulty, will help to diagnose the problem...

Is this a bluetooth keyboard, or something else? Would this be an Apple Keyboard designed for your iPad, or a third party keyboard?

At bottom right of the on-screen keyboard, you will see a Keyboard key. Tap this button to hide the on-screen keyboard.