PVE screen sharing anybody ?

Screen sharing is not related to PVE at all, and depends solely on the implementation of the Desktop Environment/Window Manager you're using. Check with their support/forums, or potentially search for how people have done this on other Debian(-based) systems. For easy remote access I'd usually recommend something like VNC or x2go, screen sharing maybe TeamViewer or a supporting remote conferencing tool (Discord, Jitsi, etc...).
 
As correctly said, PVE has nothing to do with screen sharing. For screen sharing, you need to use screen sharing applications like Webex, R-HUB web conferencing servers, Gomeetnow, Gotomeeting etc.