On the @voice portal:

When you create an Account, please ensure that you you select a Microsoft Team Service Plan. If you do not see a Microsoft Teams Service Plan, please check with your Account Manager to get that activated for you.

When creating an Account with a Microsoft Teams Service Plan, select the number of channels that is required. You can always come back to the Account and add additional channels as required.

Adding additional channels to an Account can be done at any time and directly on the portal. You will however not be able to reduce the number of channels. If you do need to reduce the number of channels due to an input error, please contact your Account Manager.

Enter the other relevant account settings that you need and click on Create Account.

When you setup an account with a Microsoft Teams Service Plan, you will be assigned a set of unique domain names. To view the domain names, click on the 'Connection' icon next to the Account in Account List. These domain names is how the @voice platform authenticates and handles the calls between accounts with Microsoft Teams. Both domains MUST be used. If only one domain is used, the account may experience degradation of their experience and may impact their overall usability of the service.

2 domain names are provided for the purpose of resiliency between various Microsoft Azure's cloud.

For now, just copy down both domain names as the domain names will need to be added to the users Microsoft Office 365 tenant account. 

Next Step: Adding the @voice Domain in Microsoft Admin Panel