You can select if this email address is to be a Catch-All Account. A Catchall account is used to collect mail for all e-mail addresses that you have not created for your domain.

If you create:

bob@mydomain.com and cindy@mydomain.com, and you made a Catch-all address called info@mydomain.com then mail addressed for anything other than bob or cindy will automatically be delivered to info@mydomain.com

So if someone emails webmaster@mydomain.com it will deliver that mail to the info@mydomain.com mailbox.

NOTE: Only one Catch-All address can exist for each domain.