Good ‘til canceled (GTC)
Good ‘til canceled (GTC) is an instruction stipulating that a trade should be kept open until it’s either executed or manually canceled. Generally, cryptocurrency trading platforms default to this option.
In stock markets, a common alternative is to close the order at the end of the trading day. Because crypto markets operate 24/7, however, GTC is more prevalent.
Immediate or cancel (IOC)
Immediate or cancel (IOC) orders stipulate that any part of the order that isn’t immediately filled must be canceled. Suppose you submit an order to buy 10 BTC at $10,000, but you can only get 5 BTC at that execution price. In that case, you would purchase those 5 BTC, and the rest of the order would be closed.
Fill or kill (FOK)
Fill or kill (FOK) orders are either filled immediately, or they’re killed (canceled). If your order instructed the exchange to buy 10 BTC at $10,000, it wouldn’t partially fill. If the entire order of 10 BTC isn’t immediately available at that price, it will be canceled.