Each refrigerator has a different way of filling the water dispenser and ice maker. Look at the instruction manual that comes with the refrigerator to verify the instructions.
Many models will have a water tank that can be found on the refrigerator side, where you will refill the water. Some also use the water from this tank to use for the ice maker.
Many water tanks cannot take hot water, drinks that use hot water like coffee or hot tea, and anything except room temp water. Adding this might damage your refrigerator.
Therefore, you should get either an electric kettle or a gas stove kettle to make drinks that require hot water.