This document discusses Office Add-ins and how they integrate with Microsoft Office and Azure Active Directory (Azure AD). It explains that Office Add-ins can be built to be fully flexible and work across private, on-premises, hybrid or cloud environments. It also notes that Office Add-ins leverage the power of Office 365 services like Office, SharePoint and Exchange Online. The document outlines the basic steps to register an Office Add-in application in Azure AD including mapping the application to the actual web service and setting the necessary permissions.