Why am I not able to see the F&O Contract for a particular scrip?

Futures and Options (F&O) contracts are only available to a subset of the exchange's listed securities. There are over 184 F&O stocks; see the full list here.

Only futures and options on these 184 tradable securities, as well as four indices, namely Nifty, Bank Nifty, Nifty Midcap Select, and Nifty financial services, are available for trading. If you can't find the F&O script for a stock, it's possible that there isn't a F&O contract for that stock.

SEBI establishes specific criteria for stocks to be included in the F&O segment. The stock can be traded in the F&O segment only if they meet the selection criteria.

At the moment, you can only trade the F&O segment on the NSE through Tiqs.