Your questions about SoFi Hong Kong are answered here

Placing an order for extended hours trading is easy. Go to the Order Ticket in the SoFi Hong Kong app, toggle the Extended Hours Trading button before placing your order. If you choose to enable Extended Hours Trading for your order, the order will be queued in the market for all applicable trading sessions (pre-market, core trading and after-hours sessions) and remain valid until it is fully executed, canceled or expired.