Hello highlandmist11,
For charging in a vehicle, there's no special accessories you would need. Cars in a foreign country use the same 12V "cigarette lighter" style outlet as US cars. If it's a more modern car, then it will most likely have USB-A or USB-C ports in it for charging just like newer cars in the US that you plug your lightning cable directly in to.
Charging in a car would be no different in another country. The power adapters are only different when charging through a regular household outlet since different countries use different plug styles and different voltages.
Cheers!