How do I know which laptop screen to order online?

My laptop screen cracked a while back and now you can't see anything on the screen. I went to the computer shop and they said it would cost 200 dollars to fix it. I don't want to pay for something I could do myself. How do I know which screen to order for my laptop. Is there a place in computer settings where I can find out what type of screen and what size I have to order online? I know I can't see the screen but I can just connect it to to the tv to find this info but the problem is I don't know how to find it.