There are different types of orders that can be executed on MT5.
For most trades, the instant execution order is sufficient since it places your buy or sell order at the current market price. However, it is always good to have a basic idea of how each type of order works, so that you can evaluate whether they may fit your trading strategy.
As the name implies, a Market Order is used to execute or open a trade at the current market rate. Basically, it is an instant buy or sell trade.
For a successful market order position to be opened, MT5 requires basic information like volume and entry price. Although not necessary, it is good to set a stop loss and take profit when placing a market order.
A Pending Order is used to open positions at a predetermined price.
Types of Pending Orders on MetaTrader 5 are: