Most computer monitors don’t offer such functions like plugging keyboards into a monitor. Because monitor cable can transfer the only video signal from computer graphical card to your monitor. But the exception is confirmed by the rule on the internet you can find monitors who have an extra USB hub inside. Those monitors have two connection to computer one USB cable and VAG, HDMI or other video transfer options.
All in one computer
One of the very popular options inside the last years is all on one computer. Those compute have everything inside the monitor. Basically, the whole computer is inside monitors so you don’t need to carry around a monitor and computer box you just have a monitor because the whole computer is based inside the monitor. Those computers often have USB ports, inside the monitor.
For this computer, you only need a keyboard and mouse and you are ready to work.