Adding metadata/keywords to pdf
What software, either Apple built-in or open-source, could add metadata/keywords to a pdf document?
I have tried Inkscape, but that overwrites metadata.
I want to add keywords specifically to an existing pdf, with no other changes.
I am investigate pdftk at least as command line tool. BigSur would be a plus, but not needed at this time.
Solution 1:
You can add keywords in Preview.
Cmd ⌘ i for the inspector.
It doesn't seem to be able to add more complex metadata though.