ISO 9001 applies to all types of organizations and businesses. It does not matter what they do or how big they are. It is focused on both service and product types of organizations and the standards of quality that are recognized throughout the world.
This is a family of standards for quality management systems and is maintained by ISO, the International Organization for Standardization which is administered by accreditation and certification bodies. A company that has been independently audited and certified to be in conformance with ISO 9001 may publicly state that it is "ISO 9001 certified" or "ISO 9001 registered.