Office 2008/2011 for Mac are 32-bit application suites. There is no update process for them as they are retired and unsupported by Microsoft, and not supported on Catalina. The current Office 365 subscription, and single-purchase Office 2019 for Mac are 64-bit Office suites and compatible with Catalina.
It is my understanding that Office 2016 for Mac and later are 64-bit applications, and if you haven't updated it for a long while, it may be 64-bit, but lacks the updates for Catalina compatibility. If it still works, you can try Microsoft AutoUpdate and see if that gets you to v16.30, but if it does not, then you will have to decide on the two current Microsoft choices from the first paragraph, or the alternative installation of the free, 64-bit LibreOffice suite, which would maintain document compatibility.