I haven't tried it on Mac, but it should. I know that XML modifications to create a new Ribbon tab should.


It is XML and vba.
I know that XML modifications work on the Mac and vba generally works fine so long as it is using Word functions. When dealing with file structure it may need alternative programming. The XML is still a stretch.


Here is my goto resource:
RibbonX: Customizing the Office Ribbon by Robert Martin, Ken Puls, and Teresa Hennig


Note that Office 365 on the Mac is a swiftly moving target. On the forums, a disproportionate number of problems arise from the Mac version. It may just be that Windows users are more used to problems and ignore them, but I don't think so. Significant revisions to the Mac version happen quickly and are expected. Sometimes there are bugs in the release version. I believe Microsoft is working very hard to satisfy Mac users.