If you need to send email messages through an e-mail address with your own domain, you have to make sure that the company will give you usage of their SMTP server. The latter is the software which enables e-mails to be sent. SMTP is an acronym for Simple Mail Transfer Protocol and it addresses all outbound e-mails from apps, webmail and contact forms. Whenever a message is sent, the SMTP server confirms with the DNS servers globally where the emails for the receiving domain name are taken care of and when it obtains this data, it creates a connection into the remote POP/IMAP server to find out if the recipient mailbox exists. In case it does, the SMTP server transmits the message body and so the receiving server sends it to the mail box where the recipient can open it and see it. Without an SMTP server on your server, you will not be capable to send out messages at all.