How to Purchase the "FUTURE" of any Stock and hold it with predefined SL to sell on any day & where to find created position in fyers?

Hi @Subir Dey9,

You can buy Futures of any stock by going to that particular scrip, right-clicking on the chart, selecting the futures chain, and placing a Buy order in the desired expiry. 

You can place a sell order (for stop loss) in futures by selecting the trigger price. However, it will be valid till the End of the day. We are working on the GTT (Good Till Trigger) order feature, and it will be implemented in the upcoming updates!