Hello ahmed KIMOO,
There are two options, georeference the model directly in the desired coordinate system, or, if the model has been georeferenced in another coordinate system, use different system in the coordinate system selection of the Export Points dialog. The second way will only work when there's a transformation available between system the model is referenced in and the output coordinate system.
But it's quite confusing, since int eh first post you are saying that points are exported in lat, long, alt format and then say that you need WGS84 coordinate system. Don't you have the desired result already?