Microsoft 365 E3 combines Office productivity applications with Windows Enterprise and enterprise mobility and security services in a per-user software subscription. Users can work with Office apps through desktop, web, and mobile experiences while IT applies a common productivity, operating-system, and endpoint-services foundation. PROD-001398 is the ordering code for this Microsoft 365 E3 offering. For endpoint environments, the suite brings together Windows Enterprise capabilities and Enterprise Mobility + Security services alongside the productivity workload. This scope supports user applications, device management, identity controls, and information-protection workflows within the same E3 service set. Assign it where users need full desktop productivity together with enterprise Windows and management capabilities, rather than a basic web-app-only productivity package. Within the Microsoft 365 family, E3 differs from entry productivity plans by adding Windows Enterprise and enterprise mobility and security components to the Office application suite. It is not a physical device, network appliance, or installable server; service access is assigned to named users. The bundle supports a consistent user platform across Office applications, Windows endpoints, identity services, managed devices, and data-protection controls. Its value lies in combining those workloads under the E3 user entitlement.