This is an Automator app built on Mac and works on a mac device
- Download PdfCombiner.app.zip and unzip
- Put PdfCombiner.app into Application folder and run
You can use it as a Service, Download 'Advanced Users - Pdf Combiner.zip' and unzip, in Service folder there is an instruction file (ReadMe.rtf).
This Automator built in MacOS Sierra, if you got Error 127 please check; https://discussions.apple.com/thread/253764288