Mac OS
Screen sharing is a built in feature of macOS. It’s integrated into the macOS finder such that you can list out the computers on your network and right click and choose to share their screen.
Third party utilies can also provide screen sharing via Virtual Network Computing (VNC).
Linux
There are many options for screen sharing on Linux. Some may come built in, depending on which Linux distribution you are using. Examples of screen sharing for Linux include UltraVNC and Remmina.
