Trading Futures STT on Expiry

Like STT issues with options, are there any tax related issues trading stock futures ? What will happen if I hold stock futures till expiry ?

You will save brokerage and charges

Can you please explain ? If I sell them I understand I have to pay Rs 20. When it expires, does it get settled in cash automatically by the broker or the exchange ? Will there be any forced squareoff on expiry ?

For Futures no sqoff. It is settled in cash as per closing price. It is same as daily cash settlement.