Merge pull request #107718 from MarileeTurscak-MSFT/patch-338

Added note about registration requirements

Author: PRMerger17

articles/active-directory/conditional-access/app-based-conditional-access.md

@@ -26,6 +26,9 @@ This article presents two scenarios to configure Conditional Access policies for
 
 In Conditional Access, this functionality is known as requiring an approved client app. For a list of approved client apps, see [approved client app requirement](concept-conditional-access-grant.md#require-approved-client-app).
 
+> [!NOTE]
+> In order to require approved client apps for iOS and Android devices, these devices must first register in Azure AD.
+
 ## Scenario 1: Office 365 apps require an approved client app
 
 In this scenario, Contoso has decided that users using mobile devices can access all Office 365 services as long as they use approved client apps, like Outlook mobile, OneDrive, and Microsoft Teams. All of their users already sign in with Azure AD credentials and have licenses assigned to them that include Azure AD Premium P1 or P2 and Microsoft Intune.