XFA (also known as XFA forms) stands for XML Forms Architecture, a family of proprietary XML specifications that was suggested and developed by JetForm to enhance the processing of web forms. It can be also used in PDF files starting with PDF 1.5 specification. XFA specification is referenced as an external specification indispensable for the application of ISO 32000-1 specification (PDF 1.7). XML Forms Architecture was not standardized as an ISO standard.
XFA's main extension to XML are computationally active tags. In addition, all instances created from a given XFA form template keep the specification of data capture, rendering, and manipulation rules from the original. Another major advantage of XFA is that its data format allows compatibility with other systems, and with changes to other technology, applications and technology standards.
According to JetForm's submission to the World Wide Web Consortium, "XFA addresses the needs of organizations to securely capture, present, move, process, output and print information associated with electronic forms." The XFA proposal was submitted to the W3C in May 1999.