I’ve got four easy hints for taking a screenshot on your Mac computer.
Press the Shift + Command + 3 keys to take a shot of the entire screen.
Press Shift + Command + 4 and you’ll be able draw a box around the portion of the screen you want a picture of.
When using Shift + Command +4 , you can press the space bar. A camera icon will pop up. You can click on any open window to grab just a screenshot of that window. You could also use it to take a picture of just one element of the screen, like the Dock.
Shift + Command + 5 brings up a tool bar that allow you capture the screen or a portion of that screen.
Click on Options and you can choose where to save the screenshot, set a timer, and decide whether you want to capture the mouse pointer.