Off market orders, or "overnight orders" are placed outside the trading hours and saved in the broker's trading system. They are automatically submitted to the exchange after the market opens on the next trading day.
Off market orders are placed in the same way as regular orders, except that they will have a "waiting for submission" status.
Investors can place off market orders after the end of the trading hours. These orders are saved by FUTU HK's trading system and automatically submitted to the exchange after the market opens on the next trading day.