how do you take a screen shot?

ctrl+prnt scrn

Print screen will save the current screen output to the Windows clipboard. There's a button or button combination that will save it somewhere in LoL's directory, I feel like it's F12 or <modifier key>+F12, but someone else should be along shortly to clarify.

make sure you go into settings and run the game in windowed mode. for some reason it pastes black screen when in full screen.

just press F12, and find the image file in LoL's directory

If you hit "Prt Sc Sys Rq" button it takes a picture of your screen and puts it into the clip board, then you have to go to paint and paste it out on paint. The modifier button to the print screen button is Alt, which only captures the currently active window, which is useful for programs that aren't taking up your whole screen.

The easiest way would be to press F12, the shortcut key for grabbing a screenshot.

Screenshots are saved in the Screenshot Folder.

By Default that would be C:\RiotGames\LeagueOfLegends\Screenshots

RoreBAWW
Riot Ambassador

push screen shot on your keyboard