If you're looking to integrate your phone with your car, you'll usually have three options: standard Bluetooth pairing, Apple CarPlay, and Android Auto. The former option provides some bare-bones functionality, usually in the form of hands-free calling and audio mirroring. Manufacturers have included this option in their vehicles for well over a decade now.
The latter two options provide a much richer experience, however. If you drive an older vehicle, you may be thinking about upgrading your factory head unit to an aftermarket model that includes more advanced integration.