How to set a 2D pic on a 3D surface?

Like: how to set a text on an animated piece of paper?

UV mapping and texturing.

If you want to make an animated page turning effect, it will be easiest to make textures of each page and apply them to a 3d model of the page. In order to bend, the page model would need to be made from a subdivided mesh (GameObject->Create Other->Plane to see an example of this kind of mesh) and the texture UVs need to be mapped from 0 to 1 on each axis. You could then rig the page model and animate it in a 3d program such as Blender, or just generate and animate the mesh procedurally in Unity (this is probably MUCH harder unless you are a good programmer with a good grasp of math!) < maybe something like this?

The easiest way to make the text is with a texture, but it might be possible in Unity to create the text from a string and render to a texture at runtime so that you can modify the text easily or have many pages without having a lot of textures.

I want to hover an image on 3d surface…
how can i do it?