.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 an 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.