Mastering Office 365 Administration

Obtaining and assigning phone numbers 

The first tab under the voice section is phone numbers, as shown in the following screenshot. This is where the numbers assigned to you will be displayed:

Voice phone numbers 

The list shows all phone numbers, their location, whether they're available or assigned, if they are a user number or a service number, and the status (hopefully, activated). 

You can filter the list by number range, number status, assignment status (user, conference, or unassigned), number type (user, service, and toll-free), and city. You can use the search function to look up a specific number, numbers starting with an area code ...