Input and output devices are parts of a computer that allows us to use. Input devices are what we put information into the computer. For example, we type on a keyboard, click with a mouse, or speak into microphone. These tools allow the computer to know and distinguish what we want it to do. Output devices are what the computer uses to give information back to us. A monitor shows pictures and words, speakers play sounds, and a printer gives us a copy on a paper. The main difference is that input devices send information into the computer, and output devices shows us the results from the computer. Some tools, like a touchscreen can work as both input and output. you can touch the screen to give input, and also see pictures on it.
Together, input and output devices make it easy for people to talk to and work with computers.