Portable Document Format (PDF) is a type of document created by Adobe back in 1990s. The purpose of this file format was to introduce a standard for representation of documents and other reference material in a format that is independent of application software, hardware as well as Operating System. PDF files can be opened in Adobe Acrobat Reader/Writer as well in most modern browsers like Chrome, Safari, Firefox via extensions/plug-ins.
A spreadsheet file contains data in the form of rows and columns. You can open, view and edit such files using spreadsheet software applications such as Microsoft Excel that is now available for both Windows and MacOS operating system. Similarly, Google sheets is a free online spreadsheet creating and editing tool that works from any web browser.
You can also convert PDF into many other file formats. Please see the complete list below.