“This file does show the date in/on/at which you paid the bill.” Which preposition is correct in this relative clause? Thanks.

On which. -is used for days and dates On which date last month did you pay your electric bill? I paid my electric bill on Tuesday, January 7th. In which- is used for years/decades/centuries. In which year did you move to your current home? I moved to my current apartment in 2023.

Tangential to your question but just FYI, your use of "does" would only be natural if you were saying this as a counter to someone saying the bill didn't show this info; e.g. Customer: *This file doesn't say when I paid the bill.* You: *Actually, this file does show the date on which you paid the bill--it's right there.* If you just want to make a general statement it's more natural to say *This file shows the date on which you paid the bill.* or even *This file shows when you paid the bill.*

I speak the language natively but I’m not sure how correct this is grammatically: “in” would be the most common/probably grammatically correct answer. “At” *may* not be grammatically correct but I hear native speakers use it. To my knowledge, “on” is just straight up incorrect. But to be honest this is speaking without me knowing all the small technical aspects of English so I’d double check with others too