Format problem with document from word 2013 to word 2016

[Meenie50]

Hi all!
I'm an author and decided to create an anthology of numerous novelettes, short stories, and flash fiction that I've written.
A couple of the stories that i'm adding are older and were written when I had Word 2003. I now have Word 2016. (This is on my computer, not online)
The paragraph settings that I'm using for my stories now are a bit different from the ones I used in the past.
When I try to change the paragraph settings on the old stories, it just doesn't work. The paragraph settings come up, I enter the formatting I want, but when I hit enter, nothing happens. The old formatting remains in place.
Not sure why this is happening. How do I address it?

Thanks!