Fill name, senders id, receivers id, subject and message, add attachments if any, click send. There you go. You can find many applications for this in hacking. Such as disguise your friend by sending a mail from any trusted company's id. You can use this service with disposable 1 click mail receiving service to receive mails to fake mail id you created and can be used to hide your identity by identity theft. The use will depend on needs. Use the logic and make use of it according to your needs.
