There are two types of forced liquidation in futures: forced liquidation by the exchange on futures companies (or self-operated members) and forced liquidation by futures companies on customers.
The exchange's forced liquidation of futures companies' positions is taken when the futures company's funds are insufficient to maintain the position (for example, because the margin ratio is increased), or the position is excessive (for example, because the position limit is reduced after entering the delivery month) A kind of coercive measure, usually the liquidation of excess positions.
The forced liquidation of customers' positions by futures companies refers to the forced liquidation of customers' positions due to insufficient funds, over-positions, etc.
For example, if you originally bought 100 lots of soybeans, the margin ratio was 10%, and the capital occupied by the position was 300,000. Now, due to the drastic changes in the market, the exchange has increased the margin ratio to 15%. Your 300,000 funds can only maintain 80 hand positions. Then either you add additional funds to continue to maintain your 100 hand positions, or the futures company closes out 20 Hand soybeans.