Applies to AutoCAD 2019, 2020 and probably other versions too.
Often I see PDF’s of drawings with silly little boxes around every piece of text and frames around images linked into drawings. Examples of this issue are shown in the screen shots below. The good news is this can easily be fixed.
For the frames around the images; Set the system variable IMAGEFRAME to 0. This will turn the frame off.
For the boxes around the text; Set the system variable EPDFSHX to 0. This will turn the boxes around the text off in the PDF output.