These commands are set up to edit the meta tags for large quantities of .pdf files.  Navigate to the folder that includes all of the .pdf files that need to have their meta tags updated.  The first command will remove all of the meta tags from all of the files.  The * wildcard can be changed to the name of a certain .pdf file if only one file needs its tags removed.  The second command will change the author tag for all of the files in the folder.  The third command will remove all of the title tags and add an author to the author tag for all of the files.  A title can be added in between the quotes to add a title for all of the files.

exiftool -all= *.pdf
exiftool -all:author='Richie Leahey' *.pdf
exiftool -Title="" -Author="Richie Leahey" *.pdf