What is a Limit order?
A limit order is one of the most basic order types. A limit order is an order to buy or sell at a specified price or better. A buy limit order (a limit order to buy) is executed at the specified limit price or lower (i.e., better). Conversely, a sell limit order (a limit order to sell) is executed at the specified limit price or higher (again, better). Unlike a market order, where you simply press "buy" and let the market choose the price, you have to specify a price when using a limit order.
If the current market price is $10000 and I want to buy a cryptocurrency lower than that at $9985, I’d place a limit order at $9985. When the market price reaches $9985 and a seller’s ask matches with the placed bid, limit order will be executed at $9985.