Office365 onmicrosoft.com domain information
Every Office365 account requires an onmicrosoft.com domain when it is first setup. You can choose a prefix that suits your business name, or the domain that you intend to use with Office365.
For example, if your business name was Widget inc, and your domain name was widgetinc.com.au, an obvious choice for your onmicrosoft.com domain prefix would be widgetinc, meaning that your inital Office365 domain name would be widgetinc.onmicrosoft.com
Once your account is setup, you will be emailed a user account to login to your Office365 admin portal. You can then configure your domain, add any users that you require (and are licensed for) and start setting up your services.
We can assist you with the initial domain configuration, user setup, DNS changes, and can also quote on assisting you with your existing email migration.