The Standalone Input Module is a pretty robust input module that will work with most of your input devices. It works with a mouse, keyboard, touchscreen, and gamepads.
The Standalone Input Module is automatically added to your EventSystem GameObject when it is created. However, you can attach the Standalone Input Module as a component using Add Component | Event | Standalone Input Module on the object's Inspector. You could do this if you wanted to add a second one, previously deleted it and want to re-attach it, or want to add the Standalone Input Module to another GameObject.
You'll see that the first four properties of the Standalone Input Module are Horizontal Axis, Vertical Axis, Submit Button, and Cancel Button ...
