I am not sure that I completely understand the question.
Do you mean, how do I import a STEP File? To import a STEP file, just open it like you would any Solidworks file.
Or are you asking, how do you convert a PDF to a STEP file? You can't, ultimately. PDF and STEP do not speak the same language. Even a 3D PDF is ultimately just an image file.
You might be able to convert a 3DPDF to an STL file, and then you would have to get some sort of mesher to convert that to a solid (FreeCAD can do this). But I don't think that there is a direct way.
I am not sure that I completely understand the question.
Do you mean, how do I import a STEP File? To import a STEP file, just open it like you would any Solidworks file.
Or are you asking, how do you convert a PDF to a STEP file? You can't, ultimately. PDF and STEP do not speak the same language. Even a 3D PDF is ultimately just an image file.
You might be able to convert a 3DPDF to an STL file, and then you would have to get some sort of mesher to convert that to a solid (FreeCAD can do this). But I don't think that there is a direct way.