A sell order is an instruction you place on a crypto exchange to sell a specific amount of an asset at a defined price or at the best available current price. It is the mechanism that converts your holding back into another asset or into cash. Every completed trade on an exchange requires a matching buy and sell order.
The exchange you use determines which order types are available, but most platforms support the core set that covers most trading needs.
Speed versus price certainty is the core tradeoff. A market order fills immediately but at an uncertain price. A limit order gives you price certainty but no guarantee of execution.
For small trades on liquid markets, a market order is usually fine. The spread between bid and ask is minimal and slippage is negligible. For large trades, a limit order prevents you from moving the market against yourself and filling at increasingly poor prices as your order eats through the available bids.
Most exchanges charge different fees depending on whether your sell order adds liquidity to the order book or removes it. A limit order that rests in the book waiting to be filled is a maker order. A market order that matches immediately against an existing bid is a taker order. Taker fees are almost always higher than maker fees because takers are consuming liquidity that makers provided.
On Binance, taker fees are 0.1% while maker fees are also 0.1% by default, but both drop with higher trading volume or BNB token holdings. On Coinbase Advanced, the spread between maker and taker fees is more pronounced, with taker fees roughly double the maker rate for lower-volume traders.
Once a sell order executes, the proceeds appear in your exchange balance in the denomination you were selling into, typically USDT, USDC, BTC, or your local fiat currency. From there you can withdraw, reinvest, or place another order. The exchange records the completed trade and issues the transaction detail in your order history, which you should retain for tax reporting purposes.
https://www.sec.gov/investor/alerts/trading101basics.pdf
https://www.coinbase.com/learn/trading-and-funding/advanced-trade-order-types
https://www.binance.com/en/support/faq/order-types