In the old version of Word I could highlight the bit of text I wanted to comment on, click on 'insert' then on 'comment', and then write the comment. Then by hovering the cursor over the highlighted bit you could see what I'd written. It also appeared as a footnote with a number.
How oh how oh how do I do this on the new version of Word?
Two ways of doing this (or at least, that I do it).
One is to go into the Tools toolbar, and then to Track Changes on that. Click on HIghlight Changes, and you will get an option to 'show changes while editing'. This then gets you into all of the editing/track changes gubbins.
Or if you go to the View menu, and then Toolbars, and choose the Reviewing toolbar, that works too.
(But I can't get it to print the footnotes on the same page as the comment any more, just in a great long list at the end, which is useless).
Giant caveat to this is that I have Word for Mac, but I'm pretty sure it's the same.