Update phone-number-management-for-united-states.md

Author: krkutser

articles/communication-services/concepts/numbers/phone-number-management-for-united-states.md

@@ -56,6 +56,8 @@ More details on eligible subscription types are as follows:
 |United Kingdom|
 |United States|
 
+[!INCLUDE [Azure Prepayment](../../includes/azure-prepayment.md)]
+
 ## Find information about other countries/regions
 
 [!INCLUDE [Country Dropdown](../../includes/country-dropdown.md)]