yes delivery settlement is applicable if options expires ITM and for OTM no there is no delivery settlement.
i don’t trade stocks fno, so I can’t comment on that. but for index i can say the margin requirement doesn’t change that much, only in rare high volatile cases exchange might increase, although its always advisable to maintain some cash over the final margin amount
As per a SEBI mandate, physical settlement is compulsory if a trader holds a position in any of the stock F&O contracts on an expiry date.
Since both positions will be netted off as in (security receivable for long futures with security deliverable for long put) and vice versa for another, there will be no physical settlement applicable in the example given above. However, delivery will be applicable in case of option expires Out the Money.
Read more about the margin requirement on our RMS policy (06 Physical settlement of F&O and Commodity) here : Risk Management Policy | Dhan
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