" I am sure to buy an adapter, but there are many types of adapter. How should I choose the correct product for my car? Do they all support my iPhone or Android phone? "
First of all, there are three adapters here, Carlinkit 4.0, Autokit and A2A.
They both support wireless carplay and wireless Android Auto. In other words, All three can be used with your phone or Android phone.
Second, please choose the right product for your car based on the following criteria:
1. For OEM Car Radios which support wired CarPlay: Carlinkit 4.0
2. For OEM Car Radios which support wired Android Auto: A2A
3. For Aftermarket Android Car Screen: Autokit
Actually, the functions of carlinkit4.0, A2A, and autokit are the same.
They all convert wired connection to wireless connection, so that the mobile phone can be connected to your car without plugging in the wire.
The difference is that they are adapted to different types of car radios.
If the radio in your car has not been modified since you bought it, then it is an OEM Car Radio. If it supports wired carplay, then you can use carlinkit4.0. If it supports wired android auto, then you can use A2A. If it supports both wired carplay and wired android auto, then it supports both carlinkit4.0 and A2A.
If your car radio has been converted to a new Android radio, then it is an aftermarket car radio and the product to buy is autokit.