Currently there's no functionality to place textures or decals on surfaces in Studio. If you just want to show something on a flat surface, then you can use a 3D image and mate it to the surface, but if you want anything more complex (like wrapped around a cylindrical surface) then you'll need to do this externally in another package and then bring the model into Studio.
If you are using Creo Parametric, the best way is to apply the Appearances and then export out a PVZ, making sure that your recipe file is setup to include textures. See PTC Article CS75925 for details.
Otherwise, I've used OBJ files with an associated MTL file with the texture images. There's a bit of a trick to getting them in correctly which was discussed in this thread: Publishing an experience with a model containing decals.
As for the reflection effect, this is achieved by using a custom shader. PTC uses this effect in the KTM Motorbike experience and you can see how that was done in this thread: Add shaders and particle system effects to models in thingworx studio.
It's worth noting that if you use a customer shader, it breaks the Chalk widget and shaders don't work in a HoloLens experience.
