how to buy the license key for VMware Workstation Pro 12?
Buy a license for Workstation Pro 16, then downgrade it to get a Workstation Pro 12 key.
https://kb.vmware.com/s/article/81665#Downgrade
Why do you need such an old version of Workstation?
@scott28tt wrote:
Why do you need such an old version of Workstation?
Probably because VMware dropped support for certain CPUs when switching to version 14+.