In theory you could upload a metadata that "contains" a 3D model, provided that it fits in the size limits (metadata can be at most 150 KB).

Otherwise, a recommended approach would be to just store your 3D model in a server, and then put the URL of the model in the metadata, so that your application can read the metadata, extract the URL and then download your 3D model from that URL.

And in which format  models will be stored, i mean excluding AssetBundles format. Can i directly save for example 3d model with fbx format, and access it in my aplication, not like in unity AssetBundle format (unity3d). 

If you use Unity, the best is to package your FBX model into an AssetBundle, and then download and instantiate the assetBundle at runtime.

If you are building (or plan to build) your application using the native SDK (Android or iOS, without using Unity), then the format is completely up to you. 

The Vuforia SDK relies on OpenGL for rendering, so it does not provide specific API to load/parse/render any 3D models in any specific format; so you would need to implement  your own model loader and renderer, or you would need to integrate a 3rd party library for 3D rendering which offers those functionalities (model loading).