The index of selling coal can be purchased through the futures market. According to relevant public information, the futures market is a standardized coal futures contract listed on domestic exchanges, including thermal coal futures of Zhengzhou Commodity Exchange and rebar futures of Shanghai Futures Exchange. Before purchasing, you need to open a trading account with a securities company or a futures company, and conduct real-name authentication and related risk assessment. When trading, you need to pay attention to the market and trading rules, and choose the right trading opportunity to trade.