In order for you to send out email messages through an email address with your very own domain, you have to make sure that the provider will provide you with access to their SMTP server. The latter is the software system which permits e-mails to be sent. SMTP is an abbreviation for Simple Mail Transfer Protocol and it handles all outbound email messages from applications, webmail and contact web forms. When a message is sent, the SMTP server confirms with all of the DNS servers throughout the world where the emails for the receiving domain name are handled and once it obtains this info, it creates a connection to the remote POP/IMAP server to check if the recipient mail box exists. If it does, the SMTP server sends the email body and so the receiving server delivers it to the mailbox in which the recipient can open it and read it. Without having a SMTP server on your server, you won't be capable to send out messages in any way.