Hi Appleron12,
Thank you for using the Apple Support Communities! I understand you are unable to connect your iPhone XR to your vehicle via CarPlay. I am happy to help.
To first answer your question, restrictions are found under Settings > Screen Time > Content & Privacy Restrictions: Use parental controls on your child's iPhone, iPad, and iPod touch - Apple Support.
When it comes to setting up CarPlay, and troubleshooting any issues with CarPlay, check out these support articles as well: Use CarPlay with your iPhone - Apple Support, and If you need help with CarPlay - Apple Support.
If you're not using CarPlay specifically, and just connecting to your vehicle's Bluetooth stereo system, you would use this article instead: How to connect your iPhone, iPad, or iPod touch to your car - Apple Support.
Best regards.