There are plenty of methods to connect your iPhone7 to your car’s stereo system, you can connect your iOS device with a compatible car stereo using Bluetooth, a USB cable, or CarPlay. This tutorial aims to show you how to connect your iPhone7 to your car via CarPlay.
Open the Settings app of your iPhone -> Click General.
Find and click CarPlay, and choose a way to connect them (via USB cable or Bluetooth). Remember to open CarPlay on your car’s display before connection.