If your meter displays three or more digits, which all DMMs do, then you will see a result. If the reading is actually meaningful is another issue. You need to check your meter specs, there will be a percentage error, plus a count error, and possibly a temperature spec, it depends on the quality of the meter as to how much data is provided. You don't say if it is AC or DC, the DC specs are usually a better.
If you need an absolute value for the voltage, and you need to know how accurate the result is, then you can determine it from the specs.
A comparative measurement is simpler, if you just need to see how much a signal varies around 5mV, for example.
Cheers,
Richard