Windows Licensing Quick Guide

Activation methods:
- KMS: Volume, 25+ machines, GVLK keys, 180-day renew
- MAK: Volume, fewer machines, internet activation
- OEM: Pre-installed, tied to firmware
- Digital: Hardware-linked, no key needed

All GVLK keys: https://windowskms.com/kms-host-keys/
Full licensing guide: https://windowskms.com/windows-licensing-guide/
slmgr reference: https://windowskms.com/slmgr-commands/
Error reference: https://windowskms.com/windows-activation-errors/