Formatting your manuscript correctly tells the person reading it (be they an editor, agent, or publisher's representative) that you are taking your book seriously—and they should too.
Here are the basics of formatting your book:
1) Save it as a Word document (.doc or .docx). Some editors are comfortable working in Pages or Google Docs, but most still prefer Word.
2) Double space it. In Word, you can do this by selecting all of the text and then going to Format and clicking Paragraph. Then select Double from the Line Spacing drop-down box.
3) Set the font as Times New Roman and the size as twelve point. Make sure the text is black.
4) Make the margins one inch. (This is usually set automatically.)
4) Delete any double spaces after periods. The rule used to be that two spaces go after a period, but now it is only one.
5) Set first-line indents instead of using tabs to indent paragraphs. To do this in Word, select all of your text and then go to Format. Select Paragraph. In the Special drop-down box by Indentation, choose First Line. Note: Some nonfiction authors choose not to use first-line indentation. In this case, a single line space (a.k.a. “paragraph break”) should come between paragraphs.
6) Insert page breaks between chapters. You can do this in Word by placing the cursor at the end of a chapter and then clicking Insert. After that, choose Break and then go to Page Break.
Extra Credit: The first line in a chapter, after a subhead, or after a numbered or bulleted list should not be indented. Hit Delete on those indentations.