I am beginner in vertex studio and i don't about an object float on water surface in vertex studio editor.Please give the suggestion as soon as possible.
Vortex will add buoyancy forces any time a geometry with buoyancy defined interacts with a fluid surface. Some background documentation:
In short, you need to have buoyancy enabled in one or more collision geometries in your part (see Enabling Buoyancy), and a fluid surface defined in your simulation (either with an Ocean extension or a Fluid Surface extension). If you have more buoyancy force (if the fluid density times the part's buoyancy volume) than the part's weight, the part will float at the surface of the fluid.
That's a high-level description, but if that is not enough to answer your questions, let us know and we can give more specific details.