These are a necessity when dealing with foreign publishers if you expect a reply as their postal services do not use United States postage stamps. You can purchase I.R.C.'s at any post office. Remember to place them inside the package with your manuscript before sealing it to mail. International Standard Book Number. A specific line of books within a publisher's offerings.
Imprints often deal with a specific genre.
Generally the font should be Courier or Times Roman in 12-point pitch as these two are the easiest to read. Avoid using italics and bold print as the publisher isn't interested in those at this stage. You can mark those words meant to be set off like that with an asterisk in front and another asterisk in back or by underlining. The print should be dark as well. An empty line should occur between paragraphs in which the scene changes or time elapses within the story.