It is likely to depend on what version of Office 365 you are using as to what options you have available.



See this link:

Customize the Ribbon and toolbars in Office for Mac

https://support.office.com/en-us/art...Newer_Versions

Try updating your version if newer options aren’t currently offered in your subscription.
Historically, Mac/Office users have not been happy about the differences between Windows and Mac versions of Office.