You can use the Reference material here to help find information about requests and fields, including:

Connection details like endpoints, methods and URIs.
Field information such as mandatory fields and maximum and minimum field lengths.

In this Section

Topic	Description
Send Document	The request you use to send Documents to the service.
Key Parameters	To prevent submitting duplicate copies of the invoice, supply a key parameter.
Correlation IDs	Use Correlation IDs to help identify related Documents.
Get Document Status	The request you use to retrieve the status of the processing.
Document Status Fields	The messages sent back by the Get Document Status request.

The VRBL Reference Guide contains the reference content for VRBL Documents.