Difference between data transfer and normal UV

I'm not sure what you mean. Are you listing three things or two? Data transfer, normal and normal uv? by normal you mean a face normal or normal as in ordinary? 

Hi Max,

Those are two completely different things and btw. it's not Normal UV's, but UV's.

So you can transfer the Normals and/or the UV's from one Object to another.

A UV Map, is simply a mapping from each 'point' of an Object to a Plane. By coloring that Plane, for instance, you know what color each point of the Object has.

By transfering the UV'S of a Monkey to a Cube, Blender looks at each 'point' of the Cube and then takes the closest (or projected, or...) 'point of the Monkey and looks where that (Monkey) point is being mapped to.