Margin Requirement is the minimum amount need to be deposited for purchasing a future or option contracts . It is certain %(percentage) of the total contract value. You need to deposit this to your broker . Many of the brokers provide different margins for intraday and carryover . In like manner it’s different for every stock and index .You can know the minimum margin Requirement to be deposited to trade by calling to your broker .In addition to this Broker’s also mention this on there website . A buyer of the call option need to pay the premium amount to get the contract .Where as the seller of the option contracts recieves this premium but the margin get blocked for him till contract is settled.
Note: The margins charged for an option seller is similar to the margin requirement for a futures contract .