The Phone app’s CarPlay integration lets you make and receive calls in your car. Opening the app lets you browse your contacts, open a dialer, review recent calls, or check your voicemail. However, since scanning through a list of contacts while driving is unsafe, you should just use Siri integration to say Call Sarah.
To message safely in the car, you can use the Messages app. Opening it lets you review your recent conversations, which is something only your passenger should do. Like with Phone, Siri makes sending messages easy. You can also have her read your received messages aloud.
Try saying Text Norah I’ll be home in 15 minutes or Read my text messages.