adaptor for iPhone 8 to connect car stereo with 3.5 mm input and charge at same time

what adaptor do I need in order to play music from my iPhone 8 through my car stereo with a 3.5 mm aux cord and charge at same time? I have read about adaptors but they always mention using with headphones. I don't want to use it with headphones, just play through my car speakers. I would like to be able to make phone calls and hear phone calls through the speakers as well.