Going back through my blog posts it looks like I first started using QCAD over 16 years ago (2009). It started with the Open Source version but then I started paying for QCAD Pro

I have sometimes received DWG CAD drawings of Site Plans and used QCAD to tweak them to show the location of comms cabinets or cabling runs.

I've even used QCAD to provide drawings for my renovations a few years back (see screenshot below)

I also love how I can run QCAD Pro on Windows, Mac and Linux.

So if you are looking for a simple, relatively easy to use CAD program that can open and export to lots of different formats then you might try QCAD.