The essence of futures is to sign a long-term contract with others to buy and sell goods (or stock index, foreign exchange, interest rate) in order to preserve value or make money. Can be long or short. Doing long means optimistic about the future rising prospects, while buying and holding is for the rising profits, so doing long means buying. Short selling is the opposite of long selling. Short sellers will sell immediately if they judge that the market is falling, so short selling is selling.
1 If investors think that the futures price will rise, they will go long. If they close their positions by rising (selling), the difference earned = closing price-opening price.
2 If investors think that the futures price will fall, they will short, fall (buy) and close their positions, and the difference earned = opening price-closing price.
In short, doing more is bullish and buying positions in operation; Short and short, sell positions in operation. Futures trading can be closed at any time, unlike T+ 1 which needs to be closed overnight. Making profits by shorting the market is the biggest feature of futures.