Format XPS, full name means XML Paper Specification, is printing type of files created by corporation Microsoft in cooperation with Ecma International. Its main task is creation of different texts starting from web pages, goes through contracts and messages and ends at notes. He´s open format and it is also called OpeN XML Paper Specification.
First release was in October in 2006. The latest version was done in June in 2009. Nowadays there is his alternative called .oxps, which is mainly used in Windows 8 due to ECMA standard. This format is not supported in older versions of Windows OS.
Tens of applications serving to open XPS format exist. First of all, there is Windows Viewer. There are also third-party applications, where we can set XPSView or XPS Viewer, both of them are for Mac OS.
After them, there is MuPDF for Linux, after that there is Okular. We can use special programs like XPS Annotator or Xara Designer Pro for Windows. To open and edit files in this file format you can use MuPDF which is very versatile. You can download it for Windows, Linux and even for Android.