Futures contracts have a specific expiration date and can be traded before the expiration. After the expiration of crude oil futures:

If "Expiration Offset" is selected, after the crude oil futures expire, the position will be automatically closed at the settlement price and the margin will be released.

If you choose "Closing Maturity", after the crude oil futures expire, if there is still open position, it will automatically close the position at the settlement price, and the released margin together with the available margin will open the same number of products in the next period. Simply put, it is to automatically close the next contract. If the available margin is not enough to open the next product of the same quantity, open the warehouse with the maximum openable quantity.