Would someone please clarify which Office program is actually being discussed?

If it is Word, then this is a feature that is clearly new to some version after 2016, which includes 2019, 2021, and 365, and it may not be all of them.
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Brian - Windows 10, 64-Bit, Version 21H1, Build 19043  

Science has become just another voice in the room; it has lost its platform.  Now, you simply declare your own truth.

       ~ Dr. Paul A. Offit, in New York Times article, How Anti-Vaccine Sentiment Took Hold in the United States, September 23, 2019