As a voltmeter to measure potential difference. Voltmeters are always placed in parallel with the voltage to be measured. With such a large resistance it draws very little current. As an ammeter to measure current.
Ammeters are always place in series with the current to be measured.
Depending on the sensitivity of the DMM this might be less than 1 ohm. As an ohmeter to measure resistance. When switched to the ohmeter setting the DMM develops a small known voltage between its terminals. When a resistor is connected across these terminals a current will flow. The DMM then acts as an ammeter to measure this current.