If, like most small companies, your firm does not have a KMS server the only time you will probably use a GVLK is if you are converting from an evaluation version of windows to a fully licensed version of Windows.
Its easiest using volume licensing and the GVLK on windows 10 in combination with Active Directory based activation. Which will be the successor of KMS. Since you are usign windows 10 and office 2016.. Forget about KMS and use AD based activation. Activate using Active Directory-based activation (Windows 10) Microsoft Docs
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