Click here to see an XDA Developers article from June 2021 called "How to take a screenshot on a Chromebook" that shows you how to both take, and edit, screenshots on your Chromebook or ChromeOS tablet.
Click here to see a ChromeUnboxed article from August 2022 called "How to get a screenshot of your Chromebook’s login screen" which may be of use sometime.
Click here to watch a ChromeUnboxed video from Feb 2021 that starts at the point where the presenter, Robbie, is talking about the updated screen capture tools.
If you are using Cloudready then note that Robbie refers to the Overview Mode key during his demonstration - this is the name ChromeOS uses for the F5 key.
A full length video that he mentions he has produced on the topic can be found here.
Click here for a ChromeUnboxed article from May 2020 called "RESIZEABLE, MOVEABLE SCREENSHOTS ARE COMING TO CHROME OS"