3594838 - How to add an attachment to the output of a billing document

How to add an attachment to the Output of a Billing Document? Is it necessary to set up an additional API? 

SAP S/4HANA Cloud Public Edition

To activate the HDM (Harmonized Document Management) which is built in into the mentioned API_CV_ATTACHMENT_SRV if HDM is activated and configuration maintained. As long as a custom document type is not created for HDM attachments, but SAT is used. And no separate API needed here. 

• Harmonized Document Management (HDM) | SAP Help Portal
• Controlling the Output Relevance and Merging of Attachments | SAP Help Portal
• API_CV_ATTACHMENT_SRV | Attachments | SAP Business Accelerator Hub

HDM, Harmonized Document Management, API, billing document, output, attachment, add , KBA , SD-BIL-IV-IF-2CL , External Billing (Public Cloud) , How To