I asked the chatbot:

The correct way to write the phrase you mentioned is "For fuck's sake." The apostrophe ('s) indicates the possessive form of the word "fuck." This expression is often used to express frustration, annoyance, or exasperation.

FFS

I thought it was "for fuck sakes" lol

Write FFS however you want. I'm most curious about the response to this work email 🤣