You may have a number of different email addresses and keeping them straight can be a handful. One of the confusing points is whether an email address is a mailbox or a domain alias. Let’s examine the difference.
Aliases also allow you to redirect messages to several mailboxes. For example, if you have a role email address, like support@mydomain.com, that can be sent to several people in your company that handle support requests.
When you register a domain for a website, it is also available to use for domain aliases.
There are lots of reasons to have domain aliases. It will make your company look more professional. If you change your mail host you don’t need to notify the people you communicate with. They will continue to use your domain alias which will now point to a new email box.
In summary: An email box is a personal inbox where emails are stored for a specific email address. A domain alias is an alternate name for an email box. An email box has physical space associated with it; a domain alias does not.