The following versions of Office have been fully tested and are supported on Windows 10. They will still be installed on your computer after the upgrade to Windows 10 is complete.
Office 2016 (Version 16)
Office 2013 (Version 15)
Office 2010 (Version 14)
Office 2007 (Version 12) is no longer part of mainstream support and hasn't been tested on Windows 10. However, Office 2007 will install and run on Windows 10. Versions of Office prior to Office 2007 are no longer supported and may not work on Windows 10.