added bot identifier for js

Author: AikoBB

articles/communication-services/concepts/includes/identifiers/identifiers-js.md

@@ -69,6 +69,36 @@ const phoneNumber = { phoneNumber: "+112345556789" };
 
 [PhoneNumberIdentifier](/javascript/api/@azure/communication-common/phonenumberidentifier)
 
+### Microsoft Bot Identifier
+
+> [!NOTE]
+> The Microsoft Bot Identifier is currently in public preview. For more information about previews, see [Supplemental Terms of Use for Microsoft Azure Previews](https://azure.microsoft.com/support/legal/preview-supplemental-terms/).
+
+The `MicrosoftBotIdentifier` interface represents a Microsoft bot with its Azure AD bot object ID. In the preview version the interface represents a bot of the Teams Voice applications such as Call Queue and Auto Attendant, and the application should be configured with a resource account. You can retrieve the Azure AD bot object ID via the [Microsoft Graph REST API /users](/graph/api/user-list) endpoint from the `id` property in the response. For more information on how to work with Microsoft Graph, try the [Graph Explorer](https://developer.microsoft.com/en-us/graph/graph-explorer?request=users%2F%7Buser-mail%7D&method=GET&version=v1.0&GraphUrl=https://graph.microsoft.com) and look into the [Graph SDK](/graph/sdks/sdks-overview).
+
+#### Basic usage
+
+```javascript
+// get the Microsoft bot's ID from Graph APIs
+const users = await graphClient.api("/users")
+                    .filter(filterConditions)
+                    .select('displayName,id')
+                    .get();
+//here we assume that you have a function getBotFromUsers that gets the bot from the returned response
+const bot = getBotFromUsers(users);
+// create an identifier
+const botIdentifier = { botId: bot.id};
+
+// if you're not operating in the public cloud, you must also pass the right Cloud type.
+// You can also specify tenantized bots by setting the isResourceAccountConfigured flag to true.
+// The flag is false if the bot is global and no resource account is configured.
+const gcchBotIdentifier = { botId: id, cloud: "gcch", isResourceAccountConfigured: true};
+```
+
+#### API reference
+
+[MicrosoftBotIdentifier](/javascript/api/@azure/communication-common/microsoftbotidentifier?view=azure-node-preview)
+
 ### Unknown
 
 The `UnknownIdentifier` interface exists for future-proofing and you might encounter it when you are on an old version of the SDK and a new identifier type has been introduced recently. Any unknown identifier from the service will be deserialized to the `UnknownIdentifier` in the SDK.