From DT Online
FreeCAD is a parametric 3D modeller made primarily to design real-life objects of any size. Parametric modelling allows you to easily modify your design by going back into your model history and changing its parameters. FreeCAD is Open Source and completely free to use - why pay more!
FreeCAD is multi platform (Windows, Mac and Linux) which can accept and output many common CAD file formats (e.g. STEP, IGES, STL, SVG, DXF, OBJ, IFC, DAE and many others). FreeCAD is aimed directly at mechanical engineering and product design but also fits in a wider range of uses around engineering (e.g. architecture or other engineering specialities), and features tools similar to Catia, SolidWorks or Solid Edge
Most fully functioning CAD software takes a little bit of getting into but FreeCAD is well supported with Tutorials, and social media user groups. Start from the User Hub and follow the Introduction. .