OS / Mac
If you have a Mac, there are few ways to take screenshots using keyboard shortcuts.
1. Use the following buttons to take a screenshot of your entire screen:
2. Use these buttons to take a partial screenshot:
3. Additionally, you can use the "control" button to make a copy of the screenshot to your clipboard:
4. Finally, you can paste the screenshot into a new document, email, etc.:
Windows
If you have a PC, there are keyboard shortcuts as well:
1. To take a screenshot of your entire screen:
Where is this button located?
2. If you would like to capture a screenshot of only one window:
3. Finally, to paste your screenshot to another document, email, etc.:
iOS
If you are trying to take a screenshot from your iPhone/iPad, make sure to click the "Home" and "Sleep/Wake" buttons simultaneously, and you should see your screen flash white.
You can find your screenshot in the 
Android
Finally, to take a screenshot using an Android device:
Look for a screenshots folder in your gallery or photos app.