Additional email addresses, or aliases, can be created for Yahoo! Business Email addresses so long as the total number of email addresses does not exceed the email address limit for the account.
How many email addresses can I set up?
Messages sent to an alias address will go straight to the inbox it is an alias for. This allows users to send and receive email from several different email addresses, but manage them from one inbox.
To create an alias or aliases:
Visit the Email Control Panel
Click the "Add Aliases" link.
Web Hosting Control Panel Add Aliases Link
Click the radio button next to the user who will manage the new alias, then click the Next button.
Web Hosting Control Panel - Add Aliases: Select User Radio Buttons
Tip: You can assign aliases only to users who have activated their email addresses. If a user has not activated the email address, the email address will be grayed out.
On the following page, you'll create the alias or aliases. You can select from commonly used aliases like sales, info, support, and contact by clicking the checkbox next to the alias(es).
You can also create your own custom alias by typing in the first part of the email address, such as customerservice or troubleshooting, in the "Create custom aliases" text field. To enter additional custom aliases, click the "Create more" link.
Web Hosting Control Panel - Add Aliases: Create Aliases Options
Click the Next button to create the alias(es)
On the confirmation page, click the Finish button.
Web Hosting Control Panel - Add Aliases: Finish Button
You can create as many aliases as you like, as long you don't exceed the number of email addresses included with your plan. (For this reason, aliases are not available to Custom Mailbox users which include only one email address.)