Acrobat DC uses fdf or xfa? I need to know how Acrobat DC saves their forms data.

Read about Widget annotations in 32000-1. And Acroform dictionaries.

Thank you two!

That's very interesting. I already tried to read the Spec but I didn't get it at all.

At the moment I collect the answers in the tracker and then I export it as a CSV to use it in excel. (But i use CSV as export format and neither FDF or XFDF or XFA format(?))

But how can I find out how the tracker knows which data is the question and which is the answer to store it correctly into the table?

Can a parser or something like that help to explain it?

My prof ask me to write a short part about the question "what does the inserted data "do" and how is it stored "during it's way through the pdf" (means 1. inserted, 2. saved,(then send via mail to the questioner) 3. converted by the tracker, 4. exported to a CSV)

And now i read a lot about the sturcture of pdf but I have no idea what or how I could describe something..

Designer is not included with Acrobat, and no longer sold as a separate product. It is effectively dead (but don't quote that in your thesis, as reality is always more complicated).

The data is not stored inside a PDF in FDF or XFDF or XFA format. These are EXPORT formats only. When it is inside the PDF, it is part of the PDF data structure, and is fully described in the PDF Specification, ISO 32000-1 (warning, 1000 page document).

Acrobat doesn't use any such format when you interact with the fields. Only when you export or import the form data does it get converted to one of those formats. XFA-forms become XML files. Acrobat-forms can be either FDF, XFDF, plain text or XML files.