Originally Kami was built as a .pdf reader for Google Drive. Over time they have added new tools and features to it making it a very powerful classroom application.
This blog post offers a short video “Crash Course in Kami” that will introduce you to the annotation tools and will offer some differentiation ideas for it as well.
If you are teaching remote learners, Kami offers a lot of assistance in accomplishing that task.
As a teacher in CESD, you have a full license to this extension.