copy-pasting comments

If you're using Word 2016, copying and pasting text to a new document should also paste the comment (I've just tried it).

The trick is to ensure you have copied the entire text that was commented on. If you only copy say part of a sentence, and the whole sentence had been selected when the comment was added, you won't get the comment come across in the paste.

Also make sure the Review tracking is set to All Markup in the new doc.