To tell if your HVAC system is electric or gas, look at the front of the heater. If you see a blue flame and hear a gas burner, it’s gas. Electric units won’t have this window and are generally silent.
If you have outdoor and indoor equipment, you have a split system. If your outdoor unit has a large fan and indoor you have a furnace (in the basement or attic), you have a furnace/AC split system.
If you have an indoor blower unit that’s not blowing hot air you likely have a heat pump outside (they look a lot like regular AC systems). If you have a heat pump installed outside and a furnace installed inside, you may have a hybrid heat pump system.
If you only have one large unit installed outside or on your roof, you have a packaged system, although these are more common for commercial buildings.
If you’re unsure, the best way to find out what type of HVAC system you have is to have a professional HVAC technician come to your home.