Several of the known DRW file types (typically vector drawings) can be exported as PDF documents, much like any pictures or other documents. Such drw to pdf conversion or export can be usually done with some dedicated export/save function in a program that can open .drw files, or with the use of a virtual PDF printer.
Open DRW file Open PDF fileA CAD converter with huge format support
An old vector-based drawing software
A free graphics editor