[b2c] phone auth update

Author: mmacy

articles/active-directory-b2c/phone-authentication.md

@@ -1,29 +1,35 @@
 ---
-title: Phone sign-up and sign-in with custom policies
+title: Phone sign-up and sign-in with custom policies (Preview)
 titleSuffix: Azure AD B2C
-description: Learn how to send one-time passwords in text messages to your application users' phones with custom policies in Azure Active Directory B2C.
+description: Send one-time passwords (OTP) in text messages to your application users' phones with custom policies in Azure Active Directory B2C.
 services: active-directory-b2c
 author: mmacy
 manager: celestedg
 
 ms.service: active-directory
 ms.workload: identity
 ms.topic: conceptual
-ms.date: 12/17/2019
+ms.date: 02/25/2020
 ms.author: marsma
 ms.subservice: B2C
 ---
 
-# Set up phone sign-up and sign-in with custom policies in Azure AD B2C
+# Set up phone sign-up and sign-in with custom policies in Azure AD B2C (Preview)
 
 Phone sign-up and sign-in in Azure Active Directory B2C (Azure AD B2C) enables your users to sign up and sign in to your applications by using a one-time password (OTP) sent in a text message to their phone. One-time passwords can help minimize the risk of your users forgetting or having their passwords compromised.
 
 Follow the steps in this article to use the custom policies to enable your customers to sign up and sign in to your applications by using a one-time password sent to their phone.
 
 [!INCLUDE [b2c-public-preview-feature](../../includes/active-directory-b2c-public-preview.md)]
 
+## Pricing
+
+One-time passwords are sent to your users by using SMS text messages, and you may be charged for each message sent. For pricing information, see the **Separate Charges** section of [Azure Active Directory B2C pricing](https://azure.microsoft.com/pricing/details/active-directory-b2c/).
+
 ## Prerequisites
 
+You need the following resources in place before setting up OTP.
+
 * [Azure AD B2C tenant](tutorial-create-tenant.md)
 * [Web application registered](tutorial-register-applications.md) in your tenant
 * [Custom policies](custom-policy-get-started.md) uploaded to your tenant