I use Onshape because it is free and I don’t need to install any software. I can simply use it anywhere there is internet, even on my cell phone. I simply click a face of my 3D model and export as DXF.
Instructions for exporting are here https://www.onshape.com/en/resource-center/tech-tips/tech-tip-importing-and-exporting-dxf-files
Once I export the DXF I use Sheetcam to create my machine code and cut it.