Here you can follow these steps the take screenshots on a Chromebook
Speed and Efficiency: They explained that keyboard shortcuts are the fastest way to do something on the computer. This method works best because the time completely dedicated to work is reduced to the minimum.
Direct Access: The shortcut can be used to take a screenshot without even opening a menu or going to an app.
Consistent Across Chromebooks: This approach applies universally to all Chromebooks and is not affected by small differences in either hardware or software.

Press the Ctrl Shift Show Windows key.
Your cursor will change.
This means that by simply placing the cursor on the screen and holding down the left mouse button we are presented with the ability to capture the specific region which was chosen.
There are also other ways, for instance, the “Screenshot” app, but this solution is, undoubtedly, the simplest and the easiest one to use on a Chromebook when it comes to screenshotting.

Read More : https://techyvibe.net/how-to-take-a-screenshot-on-a-chromebook/