Question

How is moving coil galvanometer converted to an ammeter and voltmeter?

Answer 1

A good ammeter has very low resistance. So a moving coil galvanometer is converted into an ammeter by connecting a very low shunt resistance in parallel to the galvanometer resistance.
A good voltmeter has very high resistance. So a moving coil galvanometer is converted into a voltmeter by connecting a high resistance in series with the galvanometer resistance.