package delivery company; courier service
Refers to a business that delivers parcels and packages, such as Yamato Transport or Sagawa Express.
The package delivery company delivered my parcel.
宅配便 refers to the delivery service itself or a parcel sent by such a service, while 宅配業者 specifically means the company providing the service.
Compound of 宅配 (home delivery) and 業者 (business operator).