Which of the following is NOT a method for sharing maps and apps in Portal for ArcGIS?

Sharing maps and apps in Portal for ArcGIS typically involves several built-in methods designed to facilitate collaboration and visibility among users and groups. Among these, sharing through groups allows for collaborative work, enabling users within a group to access and contribute to shared resources directly. User profiles also support sharing, as users can share content specifically linked to their profiles and manage visibility through their settings.

Public access settings enhance the sharing capabilities by enabling content to be shared openly with anyone, allowing for broader dissemination of maps and apps beyond just registered users.

In contrast, the method of sharing through private emails is not officially recognized as a standard way to share content within Portal for ArcGIS. Although users might have the option to send links or information about maps and apps via email, this is not an integrated or supported method within the platform for sharing content, making it the correct answer in this context.