Hi @Mani
Please follow the steps below to add an alias to a user account:
You must be a member of the Global admin role to add email aliases to a user.
In the admin center, go to the Users > Active users page.
On the Active Users page, select the user > Manage username and email. You won't see this option if the person doesn't have a license assigned to them.
Add the new name in the Username field, select a domain and choose Add.
Tip
The email alias must end with a domain from the drop-down list. To add another domain name to the list, see Add a domain to Microsoft 365.
When you're done, choose Save changes.
Wait 24 hours for the new aliases to update in Microsoft 365.
- The user will now have a primary address and an alias. For example, all mail sent to ******@contoso.com, and her alias, ******@contoso.com, will go to Jenna's inbox. **When the user replies, the From address will depend on her Outlook client. Outlook on the web will use the alias at which the email was received. Outlook desktop will use her primary email alias.
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