A limit order names an exact price (or better): a buy limit only fills at that price or lower, a sell limit only at that price or higher. If the market never reaches the limit price, the order simply never fills, sitting on the order book until it does, gets cancelled, or expires.
The trade-off with a market order is direct: a limit order controls price at the cost of certainty of execution, a market order guarantees execution at the cost of controlling price. Limit orders also add liquidity to the order book (they're often called "maker" orders for exactly this reason, and some exchanges charge lower fees for them) rather than taking it.
Where an exchange venue exposes them, limit orders are the more cost-conscious default for a signal that isn't time-critical, since they can avoid the slippage a market order accepts by definition.
Educational content, not investment advice. zengtrade is paper-first and non-custodial.