How i make a upload of a project to grabcad and make sure no one changes or copy my idea ?
Don't upload it :D Or get access to the GrabCAD Workbench.
you could upload an eDrawings file (make sure you do not allow the export of STL) or make a 3D pdf file. they can see your 3D CAD but cannot directly use it. but if you want keep it to your self best to not upload it.