To take a screenshot on a Chromebook:
View the site you’re experiencing difficulty with. Press Ctrl + . (For non-Chrome OS keyboards, press Ctrl + F5.) Your screenshot is saved as a PNG file in your “Downloads” folder.
To take a screenshot of a portion of the screen, press the Shift + Ctrl + Show windows keys. You’ll see a crosshair icon; click and drag it until the part of the screen you want to copy is highlighted, and then let go. Capture a specific area. Chromebook Partial Screenshot Command. In addition to a full shot, you can create a window to capture a partial screen.