.pdf File — Portable Document Format

The Portable Document Format (PDF) was developed by Adobe Systems in the early 1990s as a way to share documents across different platforms while preserving their exact formatting, fonts, images, and layout. PDF files are based on the PostScript page description language and encapsulate a complete description of a fixed-layout flat document. They have become the de facto standard for distributing printable documents worldwide. PDF supports encryption, digital signatures, embedded fonts, vector graphics, and interactive form fields. The format was standardized as ISO 32000 in 2008. PDFs are used extensively in legal, academic, business, and government contexts where document fidelity is critical. Modern PDFs can contain multimedia elements, JavaScript, and 3D artwork. The format supports accessibility features including tagged content for screen readers.