What is the difference between EMF and Voltage?

The EMF is known to be the measurement that is usually taken between the end point of the source when there is no flow that is going through it whereas the voltage is known to be the measurement that will be taken in between the two closed circuits.

The EMF also comes from the dynamo and the photodiodes while the voltage is normally used by the electric and the magnetic field. Take note that in order to measure that EMF and voltage, you cannot use the same machine or tool to do it. You would need to have an EMF meter for the EMF and the Volt Meter to measure the voltage properly.