.FDF File Extension
File TypeAcrobat Forms Data Format
File format categories include Binary, Text, XML, and Zip. The format of this file type has not been determined.
What is a FDF file?
Text file format used for data exported from .PDF form fields; typically smaller than PDF files, because they only contain form field data, not the entire form; can be created in Acrobat by selecting Advanced→Forms→Export Forms Data from the menu bar.
FDF files are commonly processed on Web servers by .CGI scripts.