A drawing database becomes a page document
DWG can contain editable drawing entities, layers, layouts, dimensions, and references used by CAD software. PDF presents a fixed page view. The conversion is useful for review and sharing, but the PDF does not replace the DWG as an editable design source.
Before exporting, identify which layout or sheet set the recipient needs. Model space may contain a drawing at full scale, while paper space arranges one or more viewports on a page. Selecting the wrong area can produce a technically valid PDF that shows the wrong portion of the design.