Time in Force

GTC (Good-til-Canceled) leaves the order on the book until it is either filled or manually cancelled/closed out.

IOC (Immediate-or-Cancel) fills any immediately available size and cancels the rest.

ALO (Post-Only) guarantees the order adds liquidity; if it were to cross book, it is cancelled instead.

This can be found by selecting for a limit order then selecting TIF and navigating the drop-down menu of options.