Some (many?) of you probably already know this, but I didn't. And I've been using Word for nearly 30 years. I have a short book almost finished, and I have the manuscript for what will become the printed version pretty much formatted in Word. To do it "right," I set it up using section breaks to end each chapter, and I used the "Odd Page" break because I want all new chapters to begin on a right-hand (odd numbered) page. I made a copy of the file and started modifying it to become the source for the e-book version. That means stripping out headers, footers, page numbers, etc., making the table of contents a series of hyperlinks, and converting footnotes to hyperlinks. That's all pretty basic. But e-books don't have odd- and even-numbered pages, so that had to change. I tried to convert the "Odd Page" section breaks to "Next Page." Nothing I tried worked. Whether I first deleted the section break and then inserted a new one, or if I first inserted a new "Next Page" section break and then deleted the "Odd Page" break -- I always ended up with the lone remaining section break being an "Odd page" break. I finally figured out that in Page Setup > Layout there's a dialogue box right at the top to set what type of breaks will be created for section breaks. I changed that from "Odd Page" to "Next Page," and the entire manuscript instantly changed, globally. Lesson learned. I never knew there was a default for that.
Word is pretty good at managing that sort of thing! One of my favourite features that few people seem to know about is the spike - multiple cut and paste. select a word in a document and press ctrl+f3 (or whatever the mac equivalent is...), the word is put onto the spike (think of a an old fashioned desk-spike with multiple memos), do this multiple times and then go to the part of the document where you want the words to appear, and press ctrl+shift+f3 (or mac equivalent?), and the multiple-cuts appear in order. If you want to copy rather than cut, just undo after after each cut (ctrl+z) - it undoes the cut but leaves the text on the spike. The most used non-standard feature that I have is a couple of macros which I have assigned to ctrl+d,t,g respectively - highlight a word and use the shortcut to either look it up in the dictionary or the thesaurus, or google it. Happy to share the code if anyone wants it.