It has been found that most of the digital multimeters are equipped to measure current up to a certain limit. And if they are used beyond their capacity then, the extra current would burn out the meter beyond repair.
The digital multimeters that are used as voltmeters are usually connected across a circuit. They can be used to perform basically two tests. While the first one relates to checking the voltage that is required to operate a component, the latter relates to voltage drop test. For the first test all you have do is connect it from the positive terminal of a component to ground. And then you can read the amount of voltage there is to operate the component. Most of the times, it will either read 0 voltage or full voltage.
The second test as has been mentioned before relates to voltage test drop. For example if a particular bulb is not working and you want to go for troubleshooting at home, all you have to do is connect digital multimeters (that is being used as voltmeter) to the light bulb circuit. If it indicates full voltage then you should know that the problem area may either be the bulb, the socket or the ground connection.
If on the other hand, you install a brand new or working bulb and still it doesn't light then the problem lies on the socket or ground. Further, connecting the voltmeter to the ground terminal of the socket and zero volts meter reading would indicate zero volts.
Digital multimeters are today the most reliable options for checking current, resistance and voltage. They give accurate readings and are very user friendly, which means that with a little bit of practice, anyone can use it as test equipment.