You can use your phone as a keyboard on a Windows PC by using Android apps and PC software. Here is a complete guide on this.

As it turns out, it’s relatively easy to use a tablet or a spare laptop as touchpad for a Windows PC. Fire Max 11 running Bluetooth Keyboard & Mouse ...

How do I connect my Bluetooth keyboard without a USB receiver? If your keyboard has a Bluetooth connectivity feature, then you don’t need a USB receiver to connect it to your PC.

The process of setting up your smartphone to use it as a mouse or keyboard is fairly simple. However, it does require the use of a third-party tool.