Using exiftool to update a custom PDF property.

README.md

Update a PDF custom property named "signature":

exiftool -config exiftool_config -signatures='[{"page":1,"x":342,"y":646}]' -form_data='[{"name":"POS-010[0].Page2[0].Sign[0].SigDate[0]","value":"[date]"}]' my.pdf

Verify the values:

exiftool  -config exiftool_config -signatures -form_data my.pdf

exiftool_config

%Image::ExifTool::UserDefined =
   (
       'Image::ExifTool::PDF::Info' =>
      {
              signatures => { },
              form_data => { },
       },
   );
1;  #end