Option expiry day

Sir… what if I trade in index like bank nifty and nifty…

Case 1. - what if I buy 2 lot of nifty/banknifty and didn’t sell or squareoff on expiry so how can I buy index physically

Case 2. - what if I sell 2 lot of Nifty/banknifty and didn’t buy or didn’t square off my position on expiry…
So do I again need to pay anything

My money will come back to my account or not
If it settles automatically then

You cannot buy the Index, Futures and Options of Nifty and Bank Nifty are cash settled.

Yes, upon expiry, any profit / loss you make will be credited to / debited from your account.

Eg. If you buy an Option at 100 and it expires at 150, upon expiry 150 * Lot Size will credited to your account.

Now if the same Option expires at 0, you will lose the entire premium paid (Rs. 100 * Lot Size).

Similarly if you Shorted an Option at 100 you immediately recieve Rs. 100 * Lot Size in your account, if this option expires at 0 you get to keep the entire premium you received.

Now if the same Option expires at 150, Rs. 150 * Lot Size will be debited from your account.

Would like to suggest you to read Options module on Varsity, everything has been explained in detail there.