Stop orders are usually used to limit potential losses in case the price suddenly rises or drops.
When you place a stop order you set an entry/exit price point. Once the price surpasses the predefined entry/exit point, the stop order becomes an instant order and gets executed. You can place your stop order here by selecting "stop" in the ”Order type” drop-down menu.
Example of stop sell order: If the current market price is 10000 USD for 1 BTC and you wish to prevent potential losses, you may set a stop sell at 9000 USD for 1 BTC. If the price drops to 9000 USD for 1 BTC, your stop sell order will be executed and your BTC will be sold.
Example of stop buy order: The current market price is 10000 USD for 1 BTC. The trader in a short position might want to set up a stop buy order for BTC at 11000 USD for 1 BTC. The price then continues to rise to 12000 USD for 1 BTC, so the trade has made a profit.
Please note that stop sell orders work in a way that when the price drops and the order is triggered, an instant sell order is placed on the market. However, do keep in mind that stop orders are not a 100% guarantee of getting the desired entry/exit points.
Slippage may occur when the volatility of the market makes an order at a specific price impossible to execute and close. In such an instance, the stop order will execute the trade at the next best price.