During a session at WWDC 2017, it seems that more details of the service was revealed. Business Chat will be part of iOS 11 (and presumably beyond) where through Safari, Maps, Spotlight, or Siri, users will be able to start conversations with businesses that support the service. In a way it almost sounds like how one might communicate with businesses through their Facebook Pages and Facebook Messenger.
However with Business Chat, Apple plans for it to be more than just a chatting platform. The company envisions how it will be able to support more complex interactions like scheduling an appointment, make bookings, and so on. One of the examples Apple showed was how customers can actually place an order, make payment using Apple Pay, and even track the shipping all within Business Chat itself.
The feature will also be integrated with other customer service platforms which includes LivePerson, Salesforce, Nuance, and Genesys. For now interactions will be completely human-to-human, unlike Facebook Messenger which allows companies to use chatbots, but that could change in the future.