Can I create character models using graphics softwares like AutoCAD, Maya or Blender without coding? If yes, how? If no, why?

Answer 1

Sure you can! You may add to your software list: Sculptris, ZBrush, Rhino3D, 3Ds Max, Lightwave, Modo and MakeHuman.
Blender and MakeHuman are free and open source. Sculptris is free as in free beer. All the other 3D software mentioned above is not only non-free but also very expensive.