A water heater, especially an electric model, is a very simple device. Unheated water enters one side of the tank. The water is heated by a couple of electric resistance elements that extend from the side of the tank into the middle of the water. And then on demand the water exits from the other side of the tank.
Unfortunately, such simplicity doesn’t really extend to its installation. While far from difficult, installing an electric water heater does involve plumbing and electrical work, which may be enough to put off quite a few people. It shouldn’t. The skills required for a job like this are not nearly as demanding as they are for other common homeowner pursuits like refinishing furniture or growing a successful vegetable or flower garden.