If you would like to send e-mails through an e-mail address with your own domain, make sure that the provider will provide you with access to their SMTP server. The latter is the software system that allows email messages to be transmitted. SMTP is an acronym for Simple Mail Transfer Protocol and it deals with all outgoing e-mails from apps, webmail and contact web forms. When a message is sent out, the SMTP server checks with all of the DNS servers globally where the emails for the receiving domain are handled and as soon as it gets this info, it connects to the remote POP/IMAP server to check if the recipient mailbox exists. In case it does, the SMTP server sends the message body and 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 end, you won't be capable to send out messages at all.