The PDF (Portable Document Format) is a file format developed by Adobe in the 1990s to present documents, including text formatting and images, in a manner independent of application software, hardware, and operating systems. Based on the PostScript language, each PDF file encapsulates a complete description of a fixed-layout flat document, including the text, fonts, vector graphics, raster images and other information needed to display it accurately. PDFs are widely used for sharing documents because they preserve the intended formatting regardless of the recipient's operating system or software. They are also commonly used for archiving documents, as they are designed to be self-contained and easily accessible in the future. PDF files can be secured with passwords and digital signatures, making them suitable for sensitive information. The format supports interactive elements such as hyperlinks, forms, and multimedia content, enhancing its versatility. PDF/A is an ISO-standardized version of PDF specialized for the digital preservation of electronic documents.