They have everything they need to contact you within the professionally formatted body of the email message. (avjobs.com)
Send a cover letter, synopsis, first chapter and marketing plan in the body of an email message to the publisher (twilighttimesbooks.com)
Submit only one email with all images attached and include the title, size, medium, and date for each of the submissions in the body of the email message. (artblogsa.com)