An order is an instruction to buy or sell on a trading venue such as a stock market, bond market, commodity market, financial derivative market or cryptocurrency exchange. These instructions can be simple or complicated, and can be sent to either a broker or directly to a trading venue via direct market access. There are some standard instructions for such orders.

A market order is a buy or sell order to be executed immediately at the current market prices. As long as there are willing sellers and buyers, market orders are filled. Market orders are used when certainty of execution is a priority over the price of execution.

A market order is the simplest of the order types. This order type does not allow any control over the price received. The order is filled at the best price available at the relevant time. In fast-moving markets, the price paid or received may be quite different from the last price quoted before the order was entered.

A market order may be split across multiple participants on the other side of the transaction, resulting in different prices for some of the shares. It is the most basic of all orders and therefore, they incur the lowest of commissions, from both online and traditional brokers.

A limit order is an order to buy a security at no more than a specific price, or to sell a security at no less than a specific price (called "or better" for either direction). This gives the trader (customer) control over the price at which the trade is executed; however, the order may never be executed ("filled"). Limit orders are used when the trader wishes to control the price, rather than the certainty, of execution.

A buy limit order can only be executed at the limit price or lower. For example, if an investor wants to buy a stock, but does not want to pay more than $30 for it, the investor can place a limit order to buy the stock at $30. By entering a limit order rather than a market order, the investor will not buy the stock at a higher price, but, may get fewer shares than he wants or not get the stock at all.

A sell limit order is analogous; it can only be executed at the limit price or higher.

A day order or good for day order (GFD) (the most common) is a market or limit order that is in force from the time the order is submitted to the end of the day's trading session. For stock markets, the closing time is defined by the exchange. For the foreign exchange market, this is until 5 p.m. EST/EDT for all currencies except the New Zealand Dollar.

Good-til-cancelled (GTC) orders require a specific cancelling order, which can persist indefinitely (although brokers may set some limits, for example, 90 days).

Immediate or cancel (IOC) orders are immediately executed or cancelled by the exchange. Unlike FOK orders, IOC orders allow for partial fills.

A conditional order is any order other than a limit order which is executed only when a specific condition is satisfied.