So there are three ways you can screenshot on a Mac and each one gives you a slightly different screenshotting option.
1. Command-shift-4 then space bar then click on a window.
Hitting the space bar turns the cursor into a little camera icon which you can move over an open window. Click on the window you want to take a screenshot of and a screenshot will be captured featuring a white border.
2. Command- shift – 3
It captures a screenshot of your entire screen
3. Command- shift -3
It turns the cursor into a cross where you can select the specific area you want to capture.