I suggest looking at the wikipedia entries for geosynchronous orbit and lists of orbits. Or play Kerbal Space Program, where you can get intimately familiar with all kinds of orbits.

If the orbit is elliptical, then “height of the orbit” varies, depending on where the satellite is in the orbit, and whether it is moving towards or away from the apogee or perigee. As an extreme example, the Infrared Space Observatory was in a highly elliptical orbit with a perigee of 1,000 km (621 mi) and an apogee of 70,600 km (43,868 mi).

If the orbit is circular, geosynchronous, and around Earth, then the standard height of the orbit is 42,164 km (26,199 mi).

You can orbit at basically any height you want, but the lower you are, the faster you have to move in order to stay in the same altitude. Objects in low-earth orbit (like the ISS) typically move about 20,000 km/hr (12,400 mph), or about half the escape velocity, while objects in a geosynchronous orbit only need to move half that speed (10,800 km/hr or 6,900 mph). The moon, by comparison, orbits Earth at a leisurely 3,683 km/hr (2,288 mph).

The higher up you want to orbit, the more expensive it is to get up there. It takes a lot of fuel to claw your way out of a gravity well. Low-earth orbit is the easiest, and if you have a lot of mass (like the ISS), it’s easier to just stick to that altitude.