For me, it's setting the Timezone. Because we've had a few ways of doing it over the years, and some of the old ones still come up in searches, I can never remember the right way to do it. But now, there's a FAQ article:

https://docs.zen-cart.com/user/new_u...pics/timezone/

So: what can *you* never seem to remember how to do, and would you be willing to write a FAQ about it?
PR instructions: https://github.com/zencart/documenta...ONTRIBUTING.md