Recommended · for some experience
Arduino UNO as a USB keyboard (HID device) [Anything Arduino] (ep 6)
Why people recommend it
Shared as a way to make an Arduino Uno act as a USB keyboard using a small extra interface circuit, with library and schematic links.
Watch for: Needs extra components; boards with native USB may be simpler
In their words
Check this video, Arduino UNO as a USB keyboard (HID device) [Anything Arduino] (ep 6), as I think this is what you are looking for.
Tas on arduino.stackexchange.com, Jan 2016. CC BY-SA.
According to this video - [video] - it can be done with the use of a serial port and a few other components It is an Uno R3
Glitched on arduino.stackexchange.com, Sept 2015. CC BY-SA.