Create your design. When the work is done, click 'File' -> 'Export'. Choose the needed storage directory, enter the name of your file, and set 'AutoCAD Interchange File (*.DXF)' as its type. Click ...

Read: How to convert OBJ to FBX using Paint 3D. 2] 3D Builder Another Microsoft app that you can try to edit OBJ files is 3D Builder. Like Paint 3D, it is also a native 3D modeling app in Windows 10.