Step 1: Sign in to your Google Admin console.
Step 2: From the Admin console dashboard, go to Users.
Step 3: Click a user's name to go to their account page.
Step 4: On the user's account page, click the Account section.
Step 5: Scroll to the Aliases section. Then click Add an alias.
Step 6: Enter an alternate user name (the part of the address that appears before the @ sign).
Step 7: Click Save Changes.
[Note: It can take 24 hours, the user will begin to receive email sent to this address.]