Update concepts.md

Author: Prakulka

articles/communication-services/concepts/sms/concepts.md

@@ -11,6 +11,7 @@ ms.date: 07/10/2023
 ms.topic: conceptual
 ms.service: azure-communication-services
 ms.subservice: sms
+ms.custom: references_regions
 ---
 
 # SMS overview
@@ -37,7 +38,7 @@ Sending SMS to any recipient requires getting a phone number. Choosing the right
 
 |Factors              | Toll-Free| Short Code | Alphanumeric Sender ID|
 |---------------------|----------|------------|-----------------------|
-|**Description**|Toll free numbers are telephone numbers with distinct three-digit codes that can be used for business to consumer communication without any charge to the consumer| Short codes are 5-6 digit numbers used for business to consumer messaging such as alerts, notifications, and marketing |  Alphanumeric Sender IDs are displayed as a custom alphanumeric phrase like the company’s name (CONTOSO, MyCompany) on the recipient handset. Alphanumeric sender IDs can be used for a variety of use cases like one-time passcodes, marketing alerts, and flight status notifications.  There are two types of alphanumeric sender IDs: **Dynamic alphanumeric sender ID:** Supported in countries that do not require registration for use. Dynamic alphanumeric sender IDs can be instantly provisioned. **Pre-registered alphanumeric sender ID:** Supported in countries that requires registration for use. Pre-registered alphanumeric sender IDs are typically provisioned in 4-5 weeks. |
+|**Description**|Toll free numbers are telephone numbers with distinct three-digit codes that can be used for business to consumer communication without any charge to the consumer| Short codes are 5-6 digit numbers used for business to consumer messaging such as alerts, notifications, and marketing |  Alphanumeric Sender IDs are displayed as a custom alphanumeric phrase like the company’s name (CONTOSO, MyCompany) on the recipient handset. Alphanumeric sender IDs can be used for a variety of use cases like one-time passcodes, marketing alerts, and flight status notifications.  There are two types of alphanumeric sender IDs: **Dynamic alphanumeric sender ID:** Supported in countries that do not require registration for use. Dynamic alphanumeric sender IDs can be instantly provisioned. **Pre-registered alphanumeric sender ID:** Supported in countries that require registration for use. Pre-registered alphanumeric sender IDs are typically provisioned in 4-5 weeks. |
 |**Format**|+1 (8XX) XYZ PQRS| 12345  | CONTOSO*       |
 |**SMS support**|Two-way SMS| Two-way SMS  | One-way outbound SMS  |
 |**Calling support**|Yes| No | No |