1.What is the translation content from iPhone to car? 2.how to display ui in the car?
How to display in the car
Did you study some tutorial, like this from Apple: https://developer.apple.com/carplay/documentation/CarPlay-App-Programming-Guide.pdf
Please read the guideline here on how to create a CarPlay App https://developer.apple.com/carplay/documentation/CarPlay-App-Programming-Guide.pdf