Hello 👋🏽!
Nope no documentation needed.
The game just needs to be playable in the browser (on the itch page). If the submission has just a game file, but nothing to play in the browser, then it gets disqualified.
Sorry for the confusion, and I hope this helps. Let me know if you have other questions!
(BTW here's last week's submissions for example -- they are all good because the games are playable on the itch page)