Making an e-mail alias means creating an email address which shares the very same mailbox with a completely different e-mail address both for the incoming as well as the outgoing e-mail messages. For example, you can make an address email@example.com and it'll be linked to its own mailbox. After that, you can make an alias firstname.lastname@example.org, which can use the mailbox of sales@ and will not use a mailbox of its own. Once you look at your emails, you will see email messages sent to either one of the two email addresses in one location, which may be more convenient in some circumstances as you will not have to sign in and out of various email addresses using webmail or create numerous email addresses in an email program. This option is often used as a substitute for forwarding messages from a single address to a new one if a number of addresses are included for contact on a website.