Extensible Markup Language (XML) is a markup language that defines a set of rules for encoding documents in a format that is both human-readable and machine-readable.
XML
TL;DR XFA is a deprecated Adobe technology that uses XML structures to handle PDF form data. While it relies on a template for layout... At IDR Solutions we are constantly working on adding new functionality and improving our applications. In my previous article “How to write JPEG images... One of the really useful features of the PDF file format is the ability to have interactive elements. These began as just simple checkboxes,... Because PDF is very much an output and display format it does not contain much text formatting information such as paragraph breaks and spaces... 
