In order for you to send out e-mail messages using an e-mail address with your very own domain, make sure that the provider will provide you with usage of their SMTP server. The latter is the software allowing emails to be sent. SMTP is an abbreviation for Simple Mail Transfer Protocol and it deals with all outbound e-mails from apps, webmail and contact web forms. When a message is sent out, the SMTP server checks with the DNS servers globally where the e-mails for the receiving domain are handled and once it acquires this information, it connects to the remote POP/IMAP server to see if the recipient mailbox is out there. In case it does, the SMTP server delivers the e-mail body and then the receiving server delivers it to the mailbox in which the recipient can open it up and see it. Without having a SMTP server on your end, you won't be allowed to mail out e-mails in any way.