Great question! Hills affect electric car driving range like hills on a treadmill affects our energy: hills take a lot more energy than flat land!
EVs are able to go up hills, in fact, the instant torque of an electric motor is better suited to pull heavy loads or drive up a hill. This, however, uses a lot of energy and will therefore put a heavier load on the battery. (Literally, as EVs are heavier vehicles!)
You can still drive an EV if you live in a region that isn’t flat but, depending on how much you use your vehicle in a day, make sure to know where public charging stations are located in case you need to use one.