Since the introduction of PDF in 1993 by Adobe Systems, a lot of improvements have been made to make it what it is today. With the introduction of each type or version, capabilities of previous versions are improved upon. For instance, the number of types of other files the latest version is compatible with is improved. Specifications arte improved upon in every subsequent version of PDF.

In this article, I will be looking at some of the commonest types of PDF file formats.

PDF 2.0

PDf 2.0 represents a major improvement in format evolution since its introduction back in 2017. This version of PDF updates and refines PDF specifications that have been accumulated over the past years. This version of PDF was created to consolidate, clarify, and clean up the specification even though it also introduces and supports new features. It was cleaned from legacy features and revised to render it easier for users to understand. With this version of PDF, developers who create PDF software now have clearer instructions that allow them to create better software to result in better user experience.

This version of PDF was created by a group of industry experts, strictly following guidelines provided by the ISO. The group that created the version was also independent and without any affiliations to any company in the industry. Thus, PDF 2.0 represents the future in the world of PDF file format.


The AU in PDF/AU stands for Universal Accessibility. PDF/AU is a specification that is used to define how PDF documents can be made readable by assistive technologies. For people who rely on assistive technologies, the computer can read PDF documents out loud for them to understand what is contained therein. When PDF files started to become popular and universally adopted in important industries such as utility, health, banking, and public services, it became important to ensure that they are readable or understandable by everyone even those that have physical disabilities.

PDF/AU files are designed with a well described and logical structure. This structure is meant to make it possible for assistive technology to identify headings in documents, lists, pictures, and footers among other elements that appear in documents. This way, the document can read the document coherently, in the correct order without repeating repetitive headings, and identifying numbering on the document.


The idea behind PDF/A is to go beyond the restrictions of time. This format was designed to allow PDF documents to offer interoperability across various platforms, computers, and software. This way, PDF documents can remain accessible even in future. This format of PDF is meant to be used in functions such as exchange of electronic documents, long-term preservation, and archiving. Electronic documents are designed to maintain their visual appearance over time no matter what systems and tools are used to produce, store, and reproduce them. The source documents for PDF/A documents can be webpages, conventional PDF documents, emails, and paper documents among many others.

You can still use a PDF converter to word to convert PDF/A documents to word documents in future like you would do with normal PDF documents.