If you're an owner or an administrator, you can grant administrative privileges to any of your users that access mail via Yahoo! (POP-only users don't have Yahoo! IDs, and therefore cannot sign in to Yahoo! to access your Email Control Panel.)
To make a user an administrator:
Visit your Email Control Panel.
Click "Edit User" under the name of the person you'd like to give administrative privileges.

Scroll down to the "Administrative privileges" section, and select the "Make this user an email administrator" checkbox.

Tip: Don't see this section? If the user has a POP-only Business Mail address, the user cannot be an administrator of your account.
Click the "Save" button.
When you're done, click "OK."
This user can now create, edit, and delete email addresses and assign administrative privileges to other email users. Be sure to let this person know about his responsibilities (he or she can learn more in our administrator resource section).