Can I use natural gas on my gas stove? Should I change the gas meter? What about gas water heaters?

Of course not. The combustion calorific value of gas and natural gas is different, so the corresponding flame head is also different. Whether it's a stove or a water heater, you should change the flame head, otherwise you may waste energy and increase exhaust gases because of insufficient combustion (danger!) and other hazards. If you change from gas to natural gas, the gas company will also change your gas meter, otherwise it may not be measured correctly.