Abstract Microsoft Visio 2021, a diagramming and vector graphics application, is part of the Office 2021 perpetual suite. Volume-licensed editions of Visio 2021 utilize Key Management Service (KMS) activation, an enterprise-friendly technology that activates clients against a local server rather than Microsoft’s online servers. This paper examines the architecture, requirements, and technical workflow of KMS activation for Visio 2021. 1. KMS Architecture Overview KMS is designed for environments with 25 or more computers. For Visio 2021 (and other Office 2021 products), the KMS host runs on Windows Server or Windows 10/11 and hosts a Microsoft Volume Activation Services role.