An email alias is an email which uses exactly the same mailbox along with the primary e-mail. For instance, you can have john@domain.com as your original email address and create an alias doe@domain.com. The 2 email addresses can share the exact same mailbox, so e-mails sent to either one of them shall be received in a single place. You can use aliases for various reasons, like talking with various teams of people or signing up on websites. For those who begin to get lots of spam, for instance, you can simply delete the alias while your original mailbox won't be changed at all and you'll retain the e-mails that you need. Aliases are often considered to be a replacement for forwarding messages from one email address to a different one if you are using several addresses for contact on your website.