Screen Shots on a Mac
CAPTURING THE ENTIRE SCREEN: These key sequences take a picture of your entire screen. Use the Control key with Command+Shift+3 when you want to paste into a document (e.g. a Google doc or Word document.)
CAPTURING A PORTION OF THE SCREEN: These key sequences take a picture of an area you select. Use the Control key with Commend + Shift + 4 when you want to paste the selected area into a document (e.g. a Google doc or Word doc.)