FDF or Form Data Format files refer to files that contain various data and related annotations of another file called PDF. Developed by Adobe Systems, files that contain the FDF extension indicate the form fields and their associated values related to the mother file that created it. Most FDF files are classified as system-generated files rather than manually created files. This simply means that these files are automatically created by their associated program or file like PDF forms which are also developed by Adobe Systems.

There are various ways to create or system-generate FDF files. One easy way is to use Adobe Acrobat and use the export data command to create forms into a file. The file created with this command becomes the FDF file. Another way to generate an FDF file is to use the Adobe FDF toolkit. Exporting information from a specific database and configure it to create an FDF file may also do the desired function. One just needs to create a simple script for this purpose. Submitting forms under Adobe Field Properties may also create FDF files by means of exporting data to an internet server.

In terms of use and function, FDF files actually perform quite a lot of tasks other than contain form data and values of PDF files for example. One basic use of FDF files is to send information to a web server and retrieve a modified form data from the same web server. The basic process starts with the FDF file sent to the server. Once the server receives it, the file will be modified and sent back to the client computer. Once the modified FDF file is in the client computer, the information displayed will now be the modified data. Another important use of FDF files is in the area of Adobe Systems data archiving.