Monitor

Here's the monitor. It looks a lot like a TV set.

A computer user spends more time looking at the monitor than anything else. The monitor needs to be tilted toward you so your neck won't need to stretch. The monitor can rotate (left and right) and it can point more up or more down. Move the monitor now. Make it comfortable for you. Is a chair part of the computer system? Well maybe not, but try going without it and see what happens. Most office chairs can be adjusted up and down. Your chair needs to be high enough to have your forearms level when you use the keyboard. Higher or lower and your wrists will be bent. Typing with bent wrists is how people get permanent wrist injuries.