The Billing Transaction object is now available in the data source and data query. Billing Transaction captures important changes on Invoice Item, Credit Memo Item, and Debit Memo Item and is mainly used for Billing Reconciliation.
The Order to Revenue feature is in the Early Adopter phase. If you are a new customer with a single entity and want to use the feature, submit a request at Zuora Global Support.
This feature will be available for existing Zuora Billing or Zuora Revenue customers in future releases.