Unable to click signature field in PDF, but works after opening on Adobe Acrobat Reader & Saving

Question

I have a pdf file ( I think it's generated or combined using pdftk, not sure).

Which is uploaded to a e-signing saas service where the customer clicks on the signature field in the pdf and the third party api let customers sign.

However, the pdf's signature field isn't clickable, until I open it in Acrobat reader and save.

I tried using ghostscript but with no success. Any idea how I can make my pdf detect signature fields?

Answer 1

This worked in my case.

Note: I had also tried using ghostscript, hexapdf, mutool,... Also, the below answer was a source of inspiration in my case: https://stackoverflow.com/a/51344208/5647479

Solution:

pdftk contract.pdf cat output works.pdf

And to see the fields after running the command:

pdftk works.pdf dump_data_fields_utf8

Works on both pdftk and pdftk-java, you can find the docs for this command in the pdftk documentation burried deep.

Aside: Had to do a lot of reading to solve this, and reading adobe specifications and other docs wouldn't be a great idea as there's no end to it.