Print Screen on a Mac

Full screen=COMMAND, SHIFT, 3
Window=COMMAND, SHIFT, 4, then spacebar
Mouse selection=COMMAND, SHIFT, 4, click and drag mouse.
Alternate Method=Macintosh HD, Applications, Utilities, and click on Grab.


Notes
File saves to desktop as a PDF.
You can open the PDF in preview and save it as a picture or other type of file