Please refer to Help Center - What topics can I ask about here?. First, under what's on-topic, there's this part:
- Investing and trading strategies, including fundamental and technical analysis
and other techniques, as practiced by retail traders and investors. (again
excluding specific recommendations and evaluation of conditions)
Second, under what's specifically off-topic, there's this part:
- Requests for specific investment buy/sell advice; e.g. "should I sell X?" or
"should I buy Y?" or "will X continue to go up?"
And here's part of your question:
[...] where I can trade option, and sell naked out of money puts on finance sector
ETF (i.e. XLF) monthly. Since bank sector has been quite flat and underperform the
[broad] market, I think this strategy will be superior than simply holding those
Essentially, your question is off-topic because the question's title begins "Should I..." and the question goes on to describe the idea of selling naked OOM puts on the finance sector. That's a specific investment and the "Should I" makes the question, more or less, a request for buy/sell advice. The part about "bank sector has been quite flat and underperform" also calls for evaluation of conditions.
Perhaps a better question to ask would be along the lines of "Here's a strategy I'm thinking of employing. [...] What are the risks and potential outcomes associated with this kind of strategy?". But don't ask whether it's a good idea, whether it is likely to be profitable given market conditions, how market conditions are likely to change, etc.
p.s. While I agree with the community voting to close the original quetion, if it were edited accordingly, I would cast my own vote to re-open.