A single PC at any one time.
Can I switch between Windows and Linux versions?
Yes. You can switch between Windows and Linux versions of VMware Workstation Pro using the same license key. If you decide to switch host operating systems, you must uninstall Workstation Pro from the host operating system you no longer plan to use.
If you plan to run VMware Workstation Pro on a Linux host and a Windows host, you need to purchase two licenses.
Workstation Pro FAQs - VMware Products