A moving coil meter uses amps to cause the magnetic pointer to move so therefore is only ever an ammeter. To use it to read volts, you connect it in series with a known high resistance, this causes a current to flow that is relative to the voltage applied (ohms law).

A digital meter works by measuring volts so to use it as an ammeter, you connect it in parallel with a low resistance to measure the voltage dropped across the resistor that is relative to the current (ohms law again).