If you need to send emails through an email address with your domain name, make sure that the company will give you usage of their SMTP server. The latter is the software system which enables e-mails to be sent out. SMTP is an abbreviation for Simple Mail Transfer Protocol and it addresses all outgoing emails from apps, webmail and contact forms. When a message is sent, the SMTP server checks with all the DNS servers throughout the world where the emails for the receiving domain name are handled and once it obtains this data, it creates a connection to the remote POP/IMAP server to see if the recipient mail box exists. If it does, the SMTP server transmits the email body while the receiving server sends it to the mail box where the recipient can open it and see it. With no SMTP server on your end, you won't be capable to mail out emails in any way.