I couldn't find any documentation for MarkupsCore Extension for the Viewer v7 from here.
Is there any reason or did I miss something?
I want to know can I refer to previous versions documentation even if I'm using the Viewer v7?
it's a known documentation issue. You can use this one instead. It's the same for v7.
https://forge.autodesk.com/en/docs/viewer/v4/reference/javascript/markupscore/
Our engineering team has a plan to provide better documentation in the future. Once we got updates from them, we will post an announcement for that. Please stay tuned with us. Cheers!