Question

what is work of heater and its structue

Answer 1

Heater is used to heat water.

Answer 2

There are many kinds of heater such as electric heater, infrared heater, solar heater and many more.
Electric heating is a process in which electrical energy is converted to heat which can be done by electric heater such as cooking. Solar water heating (SWH) is the conversion of sunlight into heat for water heating using a solar thermal collector done by solar heater.