Why I am unable to sell my holding which I bought yesterday, whenever I place order it's showing like this

It takes 2 days for the shares to get credited to your demat account. Until then, you cannot sell.

Unless you have additional margin. I don't know the exact percentage. Something like 50%, I guess.

If you have additional margin of about 50% of the transaction value, then you can sell.

Hi @SAI Bharat20,

As we checked, you have NSE stocks and you are trying to sell those stocks in BSE. Kindly select scrip in NSE and place a sell order. 

Hope this clarifies!