If you'd like to send email messages using an e-mail address with your very own domain, you have to make sure that the company will give you usage of their SMTP server. The latter is the software system that enables emails to be sent out. SMTP is an acronym for Simple Mail Transfer Protocol and it deals with all outbound email messages from apps, webmail and contact forms. Every time a message is sent out, the SMTP server checks with all the DNS servers worldwide where the e-mails for the receiving domain name are managed and when it acquires this info, it creates a connection to the remote POP/IMAP server to see if the recipient mail box exists. When it does, the SMTP server directs the message body and then the receiving server delivers it to the mail box where the recipient can open it up and read it. Without having a SMTP server on your server, you won't be able to send emails in any way.