My Arduino Uno PS/2 to USB works only in serial monitor not in other Windows apps

I'm a beginner in Arduino and recently programmed an Arduino Uno board with various PS/2 to USB converters. They work when typing in the Serial Monitor of Arduino IDE, but not in other programs such as Notepad.

How can I connect the board as HID keyboard for usual works with my PS/2 keyboard?

Thanks

Note: I used two versions of converters: PS2Keyboard

The link you provided is for code that only reads from a PS2 keyboard and prints what it reads to Serial. It doesn't emulate a PS/2 keyboard in any way nor does it send any keystrokes to the computer in any way. So you shouldn't expect to see output anywhere but in a terminal where you are reading that serial output.

If you want to create an actual HID device, then you will need one of the 32u4 Arduino boards like Leonardo that can serve as a USB host controller.