In System and Activation they only speak about Product Key which is 5 groups of 5 alphanumeric characters. There are other IDs such as for Device ID and Product ID. Many times one might see Product Key and License Key used interchangeably. The Product Key on previous versions from Win7 back was on a sticker on the computer case or on Notebooks may be in the battery compartment. I can't speak about Win8/8.1, Win10 or Win11 Retail version but the OEM versions have the key imbedded on the motherboard and Activation picks that up. There are third-party products that can extract the keys but I can't say what works or doesn't work.