Input Modules describe how the Event System will handle the inputs to the game via the mouse, keyboard, touchscreen, gamepad, and such. You can think of them as the bridge between the hardware and events.
There are four input modules provided by Unity:
- Standalone Input Module
- Hololens Input Module
- Base Input Module
- Pointer Input Module
To utilize these input modules, you attach them to your EventSystem GameObject.
You are not restricted to using these four input modules and can create your own, so if you have an input device that is not covered by one of those four, you'd create your own input module script and then attach it to the Event System.
Until the recent version of Unity, there was another input module called Touch Input Module, which was necessary for touchscreen inputs. However, this module has been depreciated and its functionality is now lumped...