is a legitimate Microsoft technology used by organizations to automate the activation of volume-licensed software like Office LTSC 2021. Corporate Environment

While KMS itself is a genuine tool, many online "KMS Activators" (like KMSpico or .txt scripts) are unofficial tools designed to bypass Microsoft's licensing. Overview of Office LTSC 2021 - Microsoft Learn

Microsoft Office LTSC (Long Term Service Channel) Professional Plus 2021 is a specialized, perpetual version of Office designed for commercial and government customers

: A KMS server only begins activating clients once it has received requests from at least 5 computers (for Office). The Risks of Third-Party "Activators"

Understanding Microsoft Office LTSC Professional Plus 2021 Activation