Why do puppies pee on beds?

Answer 1

I would say anxiety and confusion over pack hierarchy. What breed of dog is it and are you meeting it's excercise needs? The right amount of focused excercise is one of the best ways to start out handling many different issues.

Answer 2

Puppies usually pee on areas where you who rather them not when they are nervous or have not yet been trained on where they should and should not go to the bathroom.

That put aside, it is more likely for puppies to pee on beds, couches and/or carpets because that is where they are comfortable. They'd much rather rest their paws on a soft area and relieve themselves there then settle for tiled or wooden floors.

Soft surfaces in a house are the closest feeling to grass. A choice between pavement and grass the dog takes grass, same inside your house.