You should be using your “permanent home address.” Usually, this is the address where your primary parent lives. Here are some particularly tricky situations:
If you’re splitting time between two parents, use the home address where you live more often.
If you’re currently living outside “home” to attend college, don’t use your college address. Instead, use your parents’ address (probably where you lived during high school).
If you’re attending boarding school away from your parents, don’t use the boarding school’s address. Instead, use your parents’ address (probably where you lived before boarding school).