I have seen several "shenanigans" posts in which the poster was advised to check to see what "fare class paid/flown" showed for a particular flight.

On the FlyDelta app, I see that listed under specific flights that I have flown, but it is always blank. If I click on it, all that I get is a glossary of terms, not the information I am looking for.

On the full delta.com website, I don't even see a "fare class paid/shown" category.

What am I doing wrong? How do I get this information? Thanks in advance!