Until recently, when you made a copy of a Google Doc, you could only make a copy of the document itself. If was not possible to move any comments over to a copy of the doc. Until now! Google just released an update that allows you to not only copy the document, but include the comments and suggestions as well. You will see this option when you go to file then make a copy. Just tick the box to include the comments on the copy of the document.
There are times when it will be most helpful for the comments to be copied with a document. Imagine this scenario. You have a document with several paragraphs of text that you want students to read. You have inserted a couple of questions for each paragraph using the comments feature. Now each student can get a copy of the doc with the comments and they can reply directly to the comments to answer the questions.
The ability to make a copy of the comments applies to Docs, Slides, Sheets, and Drawings might seems like a minor change, but it is going to provide us with some additional ways to interact on Google documents.