In order for you to send out email messages using an e-mail address with your domain, you have to make sure that the company will provide you with usage of their SMTP server. The latter is the software enabling e-mail messages to be dispatched. SMTP is an abbreviation for Simple Mail Transfer Protocol and it handles all outgoing e-mails from apps, webmail and contact forms. Every time a message is sent, the SMTP server confirms with all the DNS servers throughout the world where the e-mails for the receiving domain are handled and when it obtains this data, it creates a connection into the remote POP/IMAP server to see if the recipient mailbox is available. If it does, the SMTP server sends the email body and so the receiving server delivers it to the mail box where the recipient can open it up and see it. Without an SMTP server on your server, you won't be able to send e-mails in any way.