The following steps will help you to set an alias for Zoho Mail:
1. Log in as Admin or Super Admin to Zoho Mail
2. Go to Settings and click on Control Panel
3. Click Mail Account
4. Select the account to which alias is to be added
5. Click Add New Alias for the selected account
6. Enter the desired alias and select the appropriate domain from drop down menu in case of multiple domains
7. Make any alias default for the account from the drop down menu.
8. Click Save