I can’t find out CarPlay App in my phone

You will need to locate the CarPlay option in your vehicle, as there is no 'app' on the iPhone. For a vehicle that supports CarPlay, plug your iPhone into a USB port. If your car supports wireless CarPlay, press and hold the voice-control button usually located on your steering wheel.

To find out how to set up CarPlay, visit Use CarPlay with your iPhone

there is no CarPlay app..

there is an area in Settings > General > CarPlay..

according to the instructions in the related article at the top left of the screen..

you'll need to make sure Siri is turned on and then plug your phone into a vehicle that supports CarPlay