- Print Screen: Press COMMAND+SHIFT+3 simultaneously to save an image of the entire screen to the Desktop
- Part of Screen: Press COMMAND+SHIFT+4 simultaneously to snip a specific area of the screen to the Desktop. When the cursor changes to a cross +, drag a box around the section you want to copy and release the mouse
- The Grab option in the Utilities folder provides more extensive options for saving screen snapshots.
Additional information on this topic is available here: Capturing Screen Shots in Macs.