Whether you're submitting a manuscript for critique or consideration by an agent or editor, there is a starndard format you should use. SCBWI provides detailed instructions for members in the article, "From Keyboard to Printed Page."
Here are notes we've pulled from that article:
1) The document (text) should be an MS Word .doc or a .pdf file.
2) Include the first 10 pages of a novel or an entire picture book text if it doesn't go over 10 pages. A synopsis or query letter is optional, will not be crituqed, but will count in the page count.
* Standard margins (1” top & bottom; 1” left & right)
* Font: 12-point Times/Times New Roman, double-spaced
* Header should contain the title of the manuscript, author’s last name, and page number, formatted to the right.
* Chapter One begins two-thirds of the way down the page; subsequent chapters begin one-third of the way down the page.
4 ) Filename: Please use your first word of title_last name (and anything else designated for submission type (ex: Story_Tatalias)