Add an email alias to a Microsoft 365 user

Updated 24 September 2026For Microsoft 365

An alias is an extra email address that delivers to the same mailbox. Use it for a role address such as sales@, or to keep an old address working after someone changes their name. Aliases are free: a user can have up to 400, and no extra licence is needed.

Add the alias

You need an admin role that can manage Exchange, such as Exchange Administrator or Global Administrator. The user needs a licence already.

Sign in to admin.microsoft.com.
Go to Users > Active users and select the person’s name.
On the Account tab, under Aliases, select Manage username and email.
Under Aliases, type the first part of the new address in Username, and choose your domain from the list.
Select Add. Repeat for more aliases if you need them.
Select Save changes.

Microsoft says a new alias can take up to 24 hours to start working, though it is often quicker.

Alias, shared mailbox or new user?

Pick the lightest option that does the job:

Alias: one person reads everything sent to the address. Free.
Shared mailbox: several people read and reply from the same address, with its own inbox. Free up to 50 GB.
New user: a real person who signs in and needs their own mailbox and apps. Needs a licence.

Sending from the alias

Receiving on an alias works straight away. Sending from an alias in Outlook on the web is a company-wide setting that Microsoft only lets admins turn on with PowerShell, and it is off for many companies. If staff need to send from a role address, a shared mailbox with Send As is usually easier. Ask Office Niaga if you want us to check the setting for you.

Changing a user’s main address

To make an alias the person’s main (primary) address, Microsoft says customers who bought through a partner may need the partner to change it. Contact Office Niaga and we will do it for you.

Still stuck

WhatsApp our support team at +60 16-916 3324.

Common issues

I cannot see Manage username and email for this person.

The option only appears for users who have a licence. Assign a licence first, or use a shared mailbox if the address belongs to a team.

Emails to the new alias bounce.

New aliases can take up to 24 hours to start working. Also check that the domain in the alias is added and verified in Settings > Domains.

When the person replies, which address does the customer see?

Microsoft says Outlook on the web replies from the alias the email was sent to, while Outlook for Windows replies from the person's main address. Check before you rely on it for customer emails.

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