Digital showers require both a hot and cold water feed and an electrical supply. There is normally a separate console that these supplies feed to which can be located in a accessible location such as in a loft space or in cupboard near the bathroom. This then has the mixed water supplies running to the shower heads or bath fillers. The controls are more like remotes which either have a thin wire or are wireless (battery operated). This is an advantage if you want a concealed shower but can’t have the location of the valve due to a solid wall.
You can get pumped or no-pumped (for high pressure systems) models to give you the optimal showering experience. They are normally 1 or 2 function (feeding one or two heads) and you can sometimes get an additional remote.
Being a digital product with a CPU (computer) has additional benefits such as time display, timer, user presets, exact temperature display.