A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
This helped me: https://superuser.com/questions/991252/ribbon-size-in-office-2016. It doesn't let you have a lot of customization, but it does allow you to toggle between a smaller ribbon and a larger ribbon. The smaller one is set for "mouse mode" while the larger one is set for "touch mode." Somehow my Word switched to the larger touch mode, which is why I started searching the web for ways to customize the ribbon size. Switching it back to the smaller mouse mode made things more like I'm used to, with a smaller ribbon (measuring top to bottom) and more useful space for my work.