Update concept-fundamentals-security-defaults.md

Author: JamesTran-MSFT

articles/active-directory/fundamentals/concept-fundamentals-security-defaults.md

@@ -44,6 +44,9 @@ Security defaults make it easier to help protect your organization from these id
 
 If your tenant was created on or after October 22, 2019, security defaults may be enabled in your tenant. To protect all of our users, security defaults are being rolled out to all new tenants at creation. 
 
+> [!NOTE]
+> To help protect organzations we're always working to improve the security of Microsoft cloud services. As part of this, tenants not actively using a form of multifactor authentication will be periodically notified for the automatic enablement of the security defaults setting. After this setting is enabled, all users in the organization will need to register for multifactor authentication. To avoid confusion, please refer to the notification you recieved and alternatively you can [disable security defaults](#disabling-security-defaults) after it's enabled.
+
 To enable security defaults in your directory:
 
 1. Sign in to the [Azure portal](https://portal.azure.com) as a security administrator, Conditional Access administrator, or global administrator.