Create user mailboxes in Exchange Online
You have to use the Microsoft 365 admin center or Exchange Online PowerShell to create an Exchange Online user mailbox. You can't create new user mailboxes using the Exchange admin center (EAC). However, after Exchange Online mailboxes are created, you can manage them using the EAC.
After you create a new mailbox using Exchange Online PowerShell, you have to assign it an Exchange Online license or it will be disabled when the 30-day grace period ends.
What do you need to know before you begin?
Estimated time to complete: 3 minutes.
You need to be assigned permissions before you can perform this procedure or procedures. To see what permissions you need, see the "Recipient Provisioning Permissions" section in the Mailbox Permissions topic.
It's a good idea to use strong passwords that are at least eight characters long, and combine uppercase and lowercase letters, numbers, and symbols.
To learn how to use Windows PowerShell to connect to Exchange Online, see Connect to Exchange Online PowerShell.
For information about keyboard shortcuts that may apply to the procedures in this topic, see Keyboard shortcuts for the Exchange admin center.
Use the Microsoft 365 admin center to create a new mailbox
You can use the Microsoft 365 admin center to create a new user account. When you assign the user account a license for Exchange Online, a mailbox is automatically created for the user. To create new user accounts in the Microsoft 365 admin center, see the following topics:
Use Exchange Online PowerShell to create a new mailbox
This example creates an Exchange Online mailbox and Office 365 user account for Holly Holt. The optional parameter ResetPasswordOnNextLogon will require the user to reset their password the first time they sign in to Office 365.
New-Mailbox -Alias hollyh -Name hollyh -FirstName Holly -LastName Holt -DisplayName "Holly Holt" -MicrosoftOnlineServicesID firstname.lastname@example.org -Password (ConvertTo-SecureString -String 'P@ssw0rd' -AsPlainText -Force) -ResetPasswordOnNextLogon $true
After you create a mailbox by running the previous command, an Office 365 user account is also created. You have to activate this user account by assigning a license. To assign a license in the Microsoft 365 admin center, see Assign or remove a license.
How do you know this worked?
To verify that you've successfully created a new mailbox, do one of the following:
In the EAC, navigate to Recipients > Mailboxes. The new user mailbox is displayed in the mailbox list. Under Mailbox Type, the type is User.
Click Refresh if the new mailbox isn't displayed at first.
In the Microsoft 365 admin center, verify that the new user account is listed and that it's been assigned an Exchange Online license.
In Exchange Online PowerShell, run the following command to display information about the new user mailbox.
Get-Mailbox <Name> | Format-List Name,RecipientTypeDetails,PrimarySmtpAddress,SKUAssigned
If a license is assigned to the mailbox, the value for the SKUAssigned property is
True. If a license hasn't been assigned, the value is blank.