How can I connect my iPhone to my car if it doesn't support CarPlay?

Depending on the system in your car, you may be able to replace the infotainment system/stereo with an aftermarket model that supports CarPlay.

You can’t connect it to the car’s display if the car doesn’t support CarPlay, but you can use the car for audio reproduction and phone calls if the car supports Bluetooth connections (most cars less than 10 years old support Bluetooth). Check the car’s manual on how to set it up.