Is it legal in UK to use Android Auto or Apple Carplay while driving?
If so is there any restriction where the phone should be or can I just put it on the seat?
As I understand in general I cannot touch the phone when the engine is on.
The hands free access provided by CarPlay means it’s legal. The only restrictions on where to put your phone are that it mustn’t block your view of the road and traffic ahead, or be a distraction. https://www.gov.uk/using-mobile-phones-when-driving-the-law