If suppose I have brought nifty 10550 CE October expiry. I waited till expire. And if assumed that nifty is moved to 11800 ( uptrend which is I expected ). Now iam at deep ITM but there are no buyers on expiry.
Then how could I excercise my nifty 10550 CE October series.

Please I could not understand this as iam new to this filed please let me understand

First of all you will never face such a scenario in respect with deep ITM option. But even though you face then you will be in profit of expiry closing - your strike price - your buy value - taxes if you let it expiry …

When you have bought a call option contract, you have paid the premium. Premium has two components - Intrinsic Value(IV) and time Value (TV)

On the date of expiry, TV become zero. So you are only left with intrinsic value which is nothing but the difference between the market price and strike price.

Now, You have two options on the date of expiry - Either you exercise the option or let the option expire automatically ( which will be exercised by the exchange)

You will get the same profit in either case which is the intrinsic value of premium.

Every trade has 2 legs - If you are standing as call option buyer who have bought a contract by paying premium there there be an option seller on the same strike who has received the premium So exchange will square off all such trades.

to the best of my understanding you should never let ITM option expire without squaring off on your own. If you let it expire you will end up paying huge taxes which will be calculated as per total contract value. Never let options expire deep ITM.