In futures & options, 100% money is required, the only margin required. In futures & options
both long & short position can be held until expiry date. Future is the agreement between buyers & sellers both have rights to buy or sell and the contract will be executed until expiry date/ end of the month.
In Option Buyer is getting right to sell in a put option, the seller has an obligation not right. In Option call option Buyer is getting right to buy, again the seller has an obligation not right. both the cases seller gets premium.
The margin is Caution deposit given in the Exchange so that no one is defaulter end of the day. MTM is day today price fluctuation may cause gain or loss has to realize in money.
Premium is money given to the seller to sign the contract. the expiry date is contracting validity or settlement date.
The strike price (or exercise price) of an option is the fixed price at which the owner of the option can buy or sell the underlying security or commodity.
lot size is the number of shares can buy in one transaction.