A family of Microsoft word processing software products for creating web, email, and print documents.
Just a little more clarification:
Office 2016 requires OS X 10.10.x [Yosemite] or later. However, it appears that Apple no longer is distributing that version of OS X [at least they're making it awfully difficult to find].
John is pointing you to its successor, OS X 10.11.x [El Capitan].
Additionally, whether you can use either of those operating systems depends on the specifications your of Mac.