21.1 Requirements for Remotely Displaying Ubuntu Applications
In order to run an application on one Ubuntu system and have it display on another system there are a couple of prerequisites. First, the system on which the application is to be displayed must be running an X server. If the system is a Linux or UNIX-based system with a desktop environment running then this is no problem. If the system is running Windows or macOS, however, then you must install an X server on it before you can display applications from a remote system. A number of commercial and free Windows based X servers are available for this purpose and a web search should provide you with a list of options.
Second, the system on which the application is being run (as opposed to the system on which the application is to be displayed) must be configured to allow SSH access. Details on configuring SSH on an Ubuntu system can be found in the chapter entitled “Configuring SSH Key-based Authentication on Ubuntu...