Files with DWG extension represent proprietary binary files used for containing 2D and 3D design data. Like DXF, which are ASCII files, DWG represents the binary file format for CAD (Computer Aided Design) drawings. It contains a vector image and metadata for the representation of the contents of CAD files.
Enhanced metafile format (EMF) stores graphical images device-independently. Metafiles of EMF comprises of variable-length records in chronological order that can render the stored image after parsing on any output device. These variable-length records can be definitions of enclosed objects, commands for drawing, and graphics properties critical to render the image accurately.
You can also convert DWG into many other file formats. Please see the complete list below.