i have Nikon D3300 DSLR with Nikon 18-55mm (VR2) lens
and i want to shoot astrophotos.
i wanna know if this possible with my camera or lens
and if not , what should i upgrade ? and what to ?
Yes, it is possible to do astrophotography with your Nikon D3300 and kit lens. You will find that lens rather limiting in terms of what you can do with it, though.
Your most important upgrade would be a lens with a much faster aperture. Something like a 50mm f/1.8 or like the Rokinon 24mm f/1.4. You want to focus manually for precision so a fast, manually focused prime lens can be a more affordable path to a wide angle lens for astrophotography.