I presume the OP is asking how a traditional electricity meter works:
The traditional and most common type of electric meter is effectively an induction motor that drives a series of geared wheels connected to indicators on the meter's face. This type of meter is designed for use with alternating current. It contains two electromagnets and an aluminium disk that is free to rotate between them. The voltage coil consumes a small and relatively constant amount of power, typically around 2 watts which is not registered on the meter. The current coil similarly consumes a small amount of power in proportion to the square of the current flowing through it, typically up to a couple of watts at full load, which is registered on the meter. The interaction of the magnetic fields produced by the coils induce eddy currents in the disk producing a force proportional to instantaneous voltage and current in the coils and that force causes the disc to rotate. Two permanent magnets near the disk's edge act as a brake on the disk in such a way that the speed of rotation is proportional to the amount of current drawn. As the disk rotates, it turns a series of gear wheels connected to the analogue 'clock' dials on the meter's face that indicate the cumulative amount of electricity consumed in kWh.
The traditional meters are being phased out in favour of more accurate digital electronic meters, in addition to measuring the energy used, electronic meters can also record other parameters of the load and supply such as maximum demand, power factor and reactive power used, and which have the ability to log usage at different times of the day. In the latest smart meter form it is able to communicate this information, via signals impressed on the power line, in real time, to the electricity supplier.