I think you need to do some checking, A GAS water heater does not normally need electrical service that large- an ELECTRIC water heater will. So- just what do you have- gas or electric?
Gas heater & electric heater both are available.
Turn off electric to water heater, depending on style, gas water heater may need electric turned off to it also. Turn off gas for gas water heater. If unfamiliar with removing and installing water heater, call a plumber.
The part that generates heat... depending if it is a gas / electric heater
Not if the water heater is electric
a stove, if it's not electric water heater, if it's not electric
Turn up the temperature on the heater. Gas or electric, there is a dial on the controls
It is a gas operated or electric operated appliance used to heat water.
A tankless electric water heater is a special kind of heater that heats water that flow in a pipe by either an electric element or a gas burner. Such heater can be found in stores like Home Depot and of course Amazon.
In a gas water heater: The gas flame warms the water, exactly the same way as a gas stove burner does for a pan of water on the stove. In an electric water heater, an element - same as an electric range element, but a different shape - heats up from electrical current, and transfers that heat to the water.