A contractor is a person or organization that provides goods or services to another organization under an agreement. The agreement defines the scope of work, terms of payment, and other conditions of the relationship.
Organizations use contractors to fill gaps in their workforce or to supplement their internal staff. For example, a company might use a contractor to fill a temporary vacancy, to get specialized expertise, or to manage a project.
In the public sector, governments use contractors to deliver services that they cannot or do not want to provide internally. For example, a government might contract with a private company to build a highway or operate a prison.