Which file format is an open standard for distributing documents?

The Portable Document Format, commonly referred to as PDF, is recognized as an open standard for distributing documents. It was developed by Adobe Systems and has become widely used for a variety of purposes, including sharing documents that are intended to be consistent across different platforms and devices. One of the key advantages of PDFs is that they preserve the formatting of the original document, making them ideal for sharing materials where appearance matters, such as graphics, text, and layout.

The standardization of PDF allows for software from various developers to create, edit, and view PDFs, ensuring broad compatibility. The openness of the PDF standard means that any developer can use the specifications to create software that works with PDF files, which has contributed to its ubiquity in document exchange environments.

The other file formats listed serve different primary purposes. PPT and DOCX are proprietary formats developed primarily by Microsoft, intended for presentations and word processing documents, respectively. TXT is a plain text format that does not support complex formatting, making it less suitable for formal document distribution compared to PDFs.