If you have an Enterprise subscription, you can run VNC Server in different modes, to provide remote access in different circumstances, and meet different needs. See a picture.
Note: If you have a Home or Professional subscription, only Service Mode is available.
By default, VNC Server runs in Service Mode to remote the desktop of a computer as though you were sitting in front of it. Both cloud connectivity and direct connectivity are available for Enterprise subscribers in this mode.
On any platform, you can run VNC Server in User Mode, though note this is not useful if the remote computer is also running Service Mode. Only direct connectivity is available.
On Linux platforms, you can run VNC Server in Virtual Mode, to create and remote virtual desktops. Only direct connectivity is available. Depending on the number of computers in your tier, you can also run VNC Server multiple times, to provide access to multiple virtual desktops. This can be done on the same Linux computer, or across different ones.