Hi, and welcome to the QCAD forum
With the QCAD GUI or without as an automated process?
Using the GUI:
If the PDF contains vector data it is as simple as opening/importing the file and save that as DXF/DWG.
If not, it can be displayed as an Image entity.
An image or bitmap can be traced over to create vector data.
It might that a PDF includes both kinds of content.
Note that an Image entity is only linked to the source and that bitmap data is not stored in the DXF/DWG drawing file.
For an image from a PDF, the image source can be located in a cache folder.
To be portable, the DXF/DWG and image file(s) must be kept together.
Without the GUI and as vector data:
See QCAD Command Line tool
dwg2dwg / pdf2dwg
Regards,
CVH