When it comes to sending your release via email, you can do so through an attachment or by directly writing it in the body of the message.  Some people suggest putting it directly into the mail to avoid the nuisance of having to open an attachment, but you can also use a link in the email to include it. In your accompanying email text, make sure to introduce yourself and the company and give a short overview of the news, preferred publication date, and other relevant information.
Now you know how to submit a press release via email. Just remember to take it slow and double-check your grammar and attachments.