You can use the Snipping Tool on Windows to grab a screenshot.
1) Click on the Start Menu
2) Type "snip" in the Search programs and files field
3) Click on "Snipping Tool"
4) You can then select a region to grab a screenshot
You can use the keyboard short cut combination"CMD+Shift+3" on MAC to grab a screenshot.
For Chromebook, you can use the keyboard short cut combination "Control+Switch window" or "Control+F5" on non-Chromebook keyboards.