As we noted in a previous blog post, we’re on a journey to simplify the Office 365 admin experience. This simplification includes streamlining how you configure your environment, such as adding new domains, and providing you with more insight so that you can efficiently monitor your service.
Add generic top-level domains from the Office 365 admin center
Adding your domains to your Office 365 service provides key benefits to your service, including the ability to use your domain in your email addresses. For example, if you own the domain www.contoso.com, you can use branded email addresses like email@example.com rather than firstname.lastname@example.org, the domain name assigned to you when you register for Office 365.
There is more, so head to : Simpler configuration and monitoring for Office 365 admins