A DWF file is a 2D/3D drawing saved in the Design Web Format (DWF) developed by Autodesk. It contains design data, which includes graphics and text. DWF files are saved in a compressed format to reduce the size of the file.
The Design Web Format was developed as a device independent and resolution independent drawing format for distributing designs. It is not intended to replace popular CAD formats, but instead it is used for saving designs in a more accessible, open format that can be opened without the need to purchase expensive CAD software.