How to Create Screenshots

Windows

Use the built-in Snipping Tool application.

1. Click the Start Menu and type "Snipping Tool"
   
2. A small window like this will appear
   
   1. Once you have this Window open the rest of the screen will have a transparent white mask on the screen. You can go ahead and select(click and drag) what you want to capture.
   2. You can also change the mode do capture a full screen or window snip as well. 
      
   3. Don't for get to save your capture. Click on the Save icon (floppy disk icon)
      

Mac

1. To capture the full window
   1. Press Command+Shift+3
2. To do a free rectangle capture
   1. Press Command+Shift+4
   2. This changes the cursor to a crosshair, which you can use to select rectangular portions of the screen.
3. To get a transparent window to pop-up
   1. Press Command+Shift+5
      
   2. From here you can select to take a screen shot of
      1. Full screen
      2. window
      3. rectangle
      4. record full screen
      5. record window

How to take a screenshot on your Mac (Apple Support).