A monitor by itself does nothing.
You need to provide it with some sort of video feed. This normally will come from a computer, but could also come from a DVD player or any other media device.
The difference between a TV and a monitor is that the TV will have the electronics to receive free to air signal and display it on the screen. A smart TV can also take an internet feed as it has a basic computer built in.
If this does not answer your question then please be a little more specific in what you ask.
Any basic computer will do the trick. Go to your local computer store and buy a cheap unit. You don't need high end graphics or CPU.
Look for a minimum 8GB RAM, 512GB HDD (or SSD), an AMD 2400G APU and a DVD drive.
You also will need to think about mouse, Keyboard and Operating System.