You can place two types of orders: limit and market. Orders can only be placed if your account has sufficient funds. Once an order is placed, your account funds will be put on hold for the duration of the order. How much and which funds are put on hold depends on the order type and parameters specified.
FUNDS ON HOLD
When placing an order, the funds for the order will be frozen. The frozen funds cannot be used for another order placement or withdrawal and will remain on hold until the order is filled or cancelled.
API KEY PERMISSIONS
Order endpoints require an "apikey".