(Picture copied from an email-unknown creator)
A writer friend and I were having a discussion/disagreement on proper format for a manuscript. She and I have different ways of formatting based on what we were told at conferences and at critique group meetings. So we decided to do a search. It was mind boggling how many bloggers and how-to sites differ in the way it should be done.
Contact information on the cover sheet only, contact information also on the first page, put the chapter title close to the heading area and start the text way down on the page, put the chapter title way down on the page and double space before starting the text.
Page numbers on the top left, page numbers on the top right, page numbers only at the bottom, put the author's name, title, and page number together, put the author's name and title together on the left, separate the page number on the right.
I could go on but since I think all of you have experienced this on your own, I won't. The two of us decided that we would stick to our own way of formatting but first we would check with the editor, agent, or publisher website for particular preferences before submitting.
The best piece of advice that one website gave, and I'm sorry I cannot give credit because I didn't make a note of it, was that the most important thing in formatting a manuscript is making it easy to read by the person receiving the submission.
I think that says it all.