A computer screen should be sitting directly in front of you and not off to the side like some offices do.
That is unless you have to have two or three computer screens then there's no way around that.
The computer monitor should also be at a height where the center of the computer monitor screen is at eye level so you don't have to constantly bend your neck looking downwards.
Having your monitor positioned correctly will improve your productivity and reduce neck pain and eyestrain and help your health as well.