Future contracts enables the buying and selling of stocks on a future date at an agreed price. Through this contract buyer gets rights to buy and seller gets rights to sell on a future date.In option trading buyer has rights to buy and no obligations. And buyer has to pays premium to the seller to contract get signed.
A futures contract gives the parties the obligation to buy or sell the stock at a specific future date.Margin is a collateral that collects from the trader to buy the share in the futures
Mark -to-market refers to accounting the fair value the asset or liability based on current market price
Premium is the money paid by the buyer of the option to contract signed.