What is the difference between a workstation and any other desktop? Workstation is a highly upgradeable computer that can handle just about any challenge you can throw at it. Workstation chassis can accept multiple GPU RAM and cores CPU units.
In the pictures below from top to bottom on mobile or left to right otherwise are the HP Z series workstations. The Z8, Z6 and the Z4. The Z8 is dual socket and most expandable followed by the single socket Z6 and the entry level Z4.