The GBG IDscan Core Engine is the component required in order to have the Address Document recognition working with the system. Once the Core Engine is installed and the journey settings are configured in the correct way then the process of scanning/testing A4 documents, such as utility bills and bank statements, is to be used as part of the journey.
Depending on the journey workflow, an A4 document could be requested after the ID has been submitted. However if you have other features enabled, such as Backside Check and Face Match, then the workflow would change in a way where these are asked before the A4 document. A request for an A4 document will always follow the ID submission, unless features such as Backside check or Facematch are enabled, in which case the workflow would change and the A4 document request will follow last