Just as in every other market where you have participated, there are two key parties to an option contract:
The buyer of an options contract (i.e., the owner) has the right to exercise the contract, let it expire worthless, or sell it back into the market before expiration. The owner of the contract is likely to exercise the contract if it’s “in the money.” To get this right, the buyer pays a premium to the seller of the option contract.
The seller, the person who sold the contract to collect the premium, is assigned when the owner of the contract exercises it. When selling a contract you can buy back the contract in the market to remove the short position. Unlike the option holder who has a right to buy or sell, the seller has an obligation to buy or sell once the buyer has exercised their right to buy or sell.