Each user needs a licence. If you don't have a spare one, buy a seat first in portal2.ozhosting.com (see Adding seats to an existing subscription). New seats can take up to 30 minutes to appear.

1. Sign in to the Microsoft 365 admin centre with an admin account.
2. Go to Users > Active users and choose Add a user.
3. Enter the name and username, choose the domain and set a password.
4. Under Product licences, tick the licence to assign.
5. Finish the wizard. The mailbox is usually ready within a few minutes.