As a writer, I learned long ago that a text I was submitting for publication had to meet the editing rules of the publisher or it wouldn’t even get read. That meant I had to know what those rules were. I discovered early on that there were two sets of rules for published texts, one for literary writing (i.e., fiction and essays) and one for news articles or periodical texts (i.e., journalism). And there are “bibles” for each style.
The final authority for the literary style is The Chicago Manual of Style: Essential Guide for Writers, Editors, and Publishers (University of Chicago Press). This weighty tome is reissued regularly. The version is I have is the fifteenth edition dated 2003, the latest of several I’ve owned and worn out over my long writing career.
The bible for journalistic writing is The Associated Press Stylebook (Associated Press). The edition I’m currently using was published in 2020.
The differences between the two styles are so small that few readers would even notice them. One is displayed on the book jacket of the Chicago Manual. It is the use of a comma before the word “and” in a series; in the journalistic style, the comma is omitted. Another is spacing before and after an em dash (that is, —). In the literary style, there are no spaces—it’s written like this. In journalism, a space is added both before and after the dash — so that it looks like this.
All that said, publishers are picky to the point of being ruthless in insisting that manuscripts submitted to them adhere to the editing and formatting rules they employ. It used to be (and presumably still is—I haven’t submitted anything new for publication in more than five years) that they would reject out of hand, and without reading, texts written according to the wrong rules.
So all you would-be authors out there, beware. Before you submit a piece to a publisher, find out what his style preferences are and revise your manuscript accordingly. Otherwise, you’re probably wasting your time.