Add Prerequisite on phisical iOS device

Author: pavelprystinka

articles/communication-services/how-tos/ui-library-sdk/callkit.md

@@ -19,6 +19,7 @@ In this article, you learn how to set up CallKit correctly by using the UI Libra
 
 ## Prerequisites
 
+- A physical iOS device. An iOS Simulator does not support CallKit functionality.
 - An Azure account with an active subscription. [Create an account for free](https://azure.microsoft.com/free/?WT.mc_id=A261C142F).
 - A deployed Communication Services resource. [Create a Communication Services resource](../../quickstarts/create-communication-resource.md).
 - A user access token to enable the call client. [Get a user access token](../../quickstarts/identity/access-tokens.md).

articles/communication-services/how-tos/ui-library-sdk/includes/pip/ios.md

@@ -10,6 +10,9 @@ ms.service: azure-communication-services
 
 For more information, see the [open-source iOS UI Library](https://github.com/Azure/communication-ui-library-ios) and the [sample application code](https://github.com/Azure-Samples/communication-services-ios-quickstarts/tree/main/ui-calling).
 
+## Prerequisites
+A physical iOS device to run the App. An iOS Simulator does not support Picture-in-picture functionality.
+
 ### Picture-in-picture setup
 
 To enable multitasking and picture-in-picture, use the `CallCompositeOptions` constructor parameters `enableMultitasking` and `enableSystemPiPWhenMultitasking`.