Options on expiry day

Suppose ,

i have sold index option and bought index Options . both are in the money . If i dont square up the position before 3:30 .

Will it be automatically exercised and they any charges?

Upon expiry ITM options will be settled at Intrinsic Value and any profit or loss you will be making will be credited to / debited from your account.

For exercised long ITM options, exchange charges STT at 0.125% of the Intrinsic Value, there is no additional STT on short options as you’ve already paid STT when you took Short position.