These days, manuscripts exist almost exclusively in electronic form. That’s certainly how it works in my case. The first, and I think only, time it is printed out before it becomes a book is when the publisher orders advanced reading copies. Gone are the days when I would print out my drafts and then store them in my refrigerator to keep them safe.
Here are a couple of screen shots of what the copy edited pages look like including my revisions in response. It’s quite easy to make global changes which is important when an author (like myself) spells names six different ways. Copy editors earn their money.