The "STP" format, also called the "STEP" format, is a three-dimensional drafting specification used by a variety of CAD, or "computer assisted drawing" programs. Some users may run into difficulties opening or importing a STEP file into a standard CAD program. "DXF" files, on the other hand, are recognised by virtually all CAD programs, and the DXF format is the closest thing to a universal CAD specification. If you are given a STEP file, you may want to convert it to DXF for greater compatibility.
FreeCAD is a free, open-source CAD modeler available for Windows, Mac, and Linux. FreeCAD can import from and export to a variety of file formats, including both STEP and DXF.
DXF/STEP Converter is a free program designed to quickly and easily convert between STEP and DFX files. Simply define your input file, click the button for "STEP to DXF," and click "Convert."
Quickstep is a STEP viewer and exporter published by CadFaster. With Quickstep, you can import, view, and convert STEP files to other CAD formats. Quickstep is available as a 14-day free trial.