If you wish to send emails using an email address with your domain name, you have to make sure that the company will provide you with access to their SMTP server. The latter is the software that permits emails to be dispatched. SMTP is an abbreviation for Simple Mail Transfer Protocol and it manages all outgoing e-mails from programs, webmail and contact forms. Every time a message is sent out, the SMTP server checks with all the DNS servers throughout the world where the emails for the receiving domain are handled and once it acquires 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 message body and then the receiving server sends it to the mail box in which the recipient can open it and read it. Without having a SMTP server on your end, you will not be capable to send e-mails in any way.