Interest charges

Can someone tell me if Delayed payment charges will be applied in below scenarios:

  1. Like if i short OTM options on expiry day and don’t square- off , then will there be any interest charges or not

No, there won’t be any interest charges (assuming the OTM options expire worthless at the end of the day).

No, there are no additional charges for letting your positions expire. OTM options will expire worthless and we an option seller, you will get to keep all the premium recieved.