In order for you to send emails using an e-mail address with your own domain name, you have to make sure that the provider will provide you with usage of their SMTP server. The aforementioned is the software system which allows emails to be sent out. SMTP is an acronym for Simple Mail Transfer Protocol and it addresses all outgoing emails from apps, webmail and contact forms. When a message is sent out, the SMTP server confirms with all the DNS servers worldwide where the e-mails for the receiving domain are managed and once it gets this data, it connects into the remote POP/IMAP server to check if the recipient mailbox is out there. If it does, the SMTP server delivers the e-mail body while the receiving server sends it to the mail box in which the recipient can open it and see it. With no SMTP server on your end, you won't be allowed to send out emails at all.