An electric water boiler is like a giant kettle that you use to heat up water very quickly using electricity. You can use it to make hot drinks like tea or coffee, or to fill a bathtub with warm water.
When you turn on the electric water boiler, electricity flows through a special wire inside the boiler, which heats up the water inside. That's why you need to plug it into an electrical outlet to use it!
Most electric water boilers have a button or dial that you turn to set the temperature you want the water to be. Once the water reaches that temperature, the boiler will stop heating it up and just keep it warm.
It's important to be careful when using an electric water boiler, because the water inside can get very hot and can burn you if you're not careful. Make sure to follow the instructions carefully and never touch the water or the boiler until it has cooled down.