Office for Mac 2011 is the version originally designed for this era of Mac computers. Install Office 2010 - Microsoft Support
Office 2010 is a Windows-only version. For Mac users around that time, Microsoft offered Office for Mac 2011 (compatible with OS X Snow Leopard through OS X El Capitan, but not officially supported on Sierra). Microsoft Office 2010 Free Download For Mac Os Sierra
However, no legitimate website, including Microsoft’s official portal, offers Office 2010 for macOS. Any site claiming to provide a “Mac version” of Office 2010 is either distributing malware, a mislabeled version of Office 2011, or a WINE wrapper. Office for Mac 2011 is the version originally
: The last version of Office 2016 that supports Sierra is 16.16.27 . Office 2011 is the version most compatible with macOS Sierra
Office 2011 is the version most compatible with macOS Sierra. Apple Support Community Compatibility: