Potential difference definition , what is SI unit of voltage

what is SI unit of voltage and Potential difference definition : As we know that water can flow from a height to downward direction.
On the same way electric charge also flows in an electrical circuit and due to this flow of charge an electric current is created in a circuit, but what thing exactly force to the charge to flow from a point to another point in any circuit ?
or what thing decide the direction of current ?
Like a water flow , the charge flows between two points due to potential difference . water flows between two points due to heights . but charge flows between two points due to “voltage” or “potential difference” .
The potential or voltage difference between two points decide the flow of charge or current in electrical circuit.
” charge or electric current flows from a higher potential/voltage point to lower potential/voltage point.
more potential difference b/w two points cal faster flow of electric charge .
we generally said voltage in the name of “potential difference ” . we calculate voltage /potential difference in Volt.
It is denoted by “V” symbol.