Adding a mailbox takes two steps: buy a licence (seat), then create the user.
1. Buy a seat
Log in to portal2.ozhosting.com and add a seat to your subscription. See Adding seats to an existing subscription. New seats can take up to 30 minutes to appear in Microsoft 365. Prefer us to do it? Call Sales on 1300 467 843 (option 3).
2. Create the user
Follow Add a new Microsoft 365 user and assign the new licence. The mailbox is ready a few minutes later.
Need a shared address like info@ or accounts@? A shared mailbox doesn't need a licence. In the admin centre go to Teams & groups > Shared mailboxes > Add a shared mailbox. For an extra address on an existing mailbox, see the alias article in this section.