activate the community-made Blender add-on that enables support for the DXF format:
Open Blender.
Click “Edit > Preferences” in the top-left part of the interface.
On the pop-up page, click “Add-ons” from the left-side menu.
In the “Add-ons” page, at the top of the screen, select “Community”.
Locate the “Import-Export: Import AutoCAD DXF Format (.dxf)” and “Import-Export: Export AutoCAD DXF Format (.dxf)” options.
Activate these two community add-ons by checking the box next to them. The features will activate immediately.