Requirements:

•    Windows Powershell ISE w/ MS Teams Module installed
•    MS Teams Administrator Access

Step1: 

• Open Powershell ISE as an Administrator and connect to MS Teams
• Connect to MS Teams by running the following command: 

       Connect-MicrosoftTeams

• Run the following command to enable direct routing and assign a phone number to a user:

          Notes: Replace identity email address and phone number w/ the correct information

Get-CsPhoneNumberAssignment -Identity user@microsoft.com -PhoneNumber +19999999999 -PhoneNumberType DirectRouting

• Run the following command to Grant Direct Routing Voice Routing Policy to the user

Grant-CsOnlineVoiceRoutingPolicy -Identity user@microsoft.com -PolicyName "US Only"

   Notes: If the policy name is incorrect, run Get-csonlinevoiceroutingpolicy to get the accurate information.