Key Management Service (KMS) is not a "feature" of Microsoft 365 in the sense of a user tool like Excel or Teams; rather, it is an used by organizations to manage licenses for volume editions of Microsoft software.
(the subscription version) usually activates via the cloud-based Office Licensing Service, requiring a user sign-in and an internet connection every 30 days. However, KMS is the standard for Office LTSC microsoft office 365 kms
or organizational sign-in. It requires periodic internet connection to verify your subscription status. Volume Licensed Office (KMS): activation technology Key Management Service (KMS) is not
Key Management Service (KMS) is a Microsoft volume activation technology that allows organizations to activate Microsoft Office on systems within a local network without connecting each device to Microsoft’s servers. This paper clarifies the distinction between Office 365 subscription-based activation and KMS-based volume licensing, then provides a technical guide for deploying, configuring, and troubleshooting KMS for Microsoft Office 2019, 2021, and 2024 LTSC (Long Term Servicing Channel) editions. It requires periodic internet connection to verify your
Always verify your licensing type: if your agreement says “Microsoft 365 Apps for enterprise” or any Office 365 plan, KMS is not applicable. If your agreement says “Office LTSC Professional Plus 2024 – Volume License,” then KMS can be configured as described.
The short answer is: However, to fully understand why, we need to break down what KMS is, how Office 365 activates instead, and where KMS still fits in the modern Microsoft ecosystem.
When people search for "Office 365 KMS," they are usually looking for a way to activate the subscription version without a subscription—which is impossible and violates Microsoft’s terms. The legitimate answer is: deploy Microsoft 365 Apps for Enterprise via volume licensing.