Hello there,
Working of Digital Multimeter:
A digital multimeter (DMM) is a multifunctional meter that displays it's electrical quantitative values on an LCD screen. It can read the voltage, current, and resistance, like the analog multimeter. DMM has the ability to display the measured electrical values quickly, and without any computation.

There are two types of DMM:
1. Scalable Digital Multimeter
2. Auto-ranging Digital Multimeter

In DMM, the input signal, that is, voltage, current, resistance, temperature, or any other parameter is converted to DC voltage within the range of the ADC.

Hope this answer helps you.
Thank you!!