Hello, Could you explain how to importing 3ds max,
c4d, fbx and 3dm files in AutoCAD?Thanks  

Yeah, first you have to learn which file types can be imported into AutoCAD before attempting to do so.  A quick Internet search should provide you with that information.  If the file type you want to import is on the list then you are good to go.  If it isn't then you'll need to find a 3rd-party conversion program or use an entirely different program other than AutoCAD.