Hello @Casimiro, Sophia (PARKS) The Bookings API includes a BookingAppointment resource which represents a customer appointment for a bookingService provided by a Microsoft Bookings business. The appointment resource has a
customerNotes property where your customer can add notes associated with the appointment such as the family booking according to your use case.
Please note the bookings API is currently under the /beta version in Microsoft Graph and is subject to change. Use of these APIs in production applications is not supported. You can also view the Bookings roadmap for the upcoming features for Bookings.
Please let me know whether this helps.