Emf is potential difference generated at the two end of a source when no current is flowing.
Voltage is the difference of electrical potential between two points of an electric circuit while a current is flowing.
 
						

							
Brother, 
                 emf is the potential difference of entire circuit. I.e. internet resistance of battery is also consider while calculating the emf.
    emf is given by:-
                             E=I/(R+r)            where R is externel resistance , r is internet resistance of battery.
 Voltage is the potential difference between two terminals of battery. I.e. internet resistance of battery will not considered while calculating voltage.
        Voltage is given by:-
                                    V=I/R      
						

							
Emf is the voltage of the cell it is present even when no current is flowing ,whereas every component of a circuit can have different voltages  .also voltage does not exist in any component if current is not flowing in the circuit .