DWF Viewer

[ActCAD]

DWF is a design web format which allows you to view and print the files. DWF viewer is developed by IntelliCAD. It compresses highly rich files, who needs to view, edit or print.

DWFX file:
It is the advanced version of the DWF file format. The DWFx runs on XML platform, so we can view or print with XPS viewer and XPS viewer is a free programme which is distributed by windows operating system.

Differences:
DWF and DWFX files are highly rich files to view or print over the internet. You can read the markups, plot, change your drawings, change markup status and republish to DWF or DWFX for further design.

DWFX files are larger than corresponding DWF file. We mostly use the DWFX file format to share the design data with viewers.
https://actcad.com/blog/best-dwf-viewer/