Are you asking about a specific, potentially unofficial, software tool, or KMS client activation and product keys - Microsoft Learn
KMS (Key Management Service) Activation Helper is a software tool designed to assist users in activating their Windows operating system and Microsoft Office products using the KMS activation method. The KMS activation method is a popular choice for organizations and individuals who need to activate multiple copies of Windows and Office. kms activation helper v15 64bit hot
Safer alternatives and best practices
Instead of connecting to a legitimate corporate or Microsoft-hosted server, the software creates a local "KMS Server" on the host machine or redirects the system's activation requests to a remote, unofficial server. Are you asking about a specific, potentially unofficial,