In SAP ERP FI, there are generic framework for output management called "Correspondence", which is used to manage the output request triggered by application like Document Entry or Document Display, it is also applicable for case with detailed line item level.
A generic output management shall encapsulate the generation of output content in a given format(PDF or e-Mail for example), the communication channel for output sending, also a preview and output feature for generated document shall be built in. Besides above basic features, there are requirements that customers should be able to customize the Output Layout(like PDF Template Layout, e-Mail Template with variable), a standard extension is a must.
SAP Correspondence is a given approach output management framework used by SAP FI, its block diagram can be depicted below:
The Application is the access point in daily works of a business user, like a Account Payable Role should be able to print a payment receipt if he or she is entering the payment document in SAP ERP. Provided the configuration is done correctly, the business user just can trigger a correspondence in Payment Entry Application, an output request will be sent to correspondence DB (BKORM), after processing payment document is done, the user would like to check all output request he/she has sent, a dedicated application(Correspondence Monitor) can be used to manage all output request item in business user level. The monitor application will read the configuration to delegate correct print program to do data retrieval and output content generation, then it will be sent to spool request, where user can determine the previewing and sending of the generated output file, no matter it is a PDF or e-Mail.
Above all is the existing technology for on-premise, in case cloud system the case is much more difficult as customers have limited access to dedicated infrastructure, like printer set-up, communication channel set-up and etc, there are more tasks should be done by output management framework to enable output in cloud system, but the advantage is that TCO is reduced from customer perspective, it is much easier to use without any complicated system set-up, a detailed overview of SAP Output Management in S/4 Cloud you can go to below two links:
Moving to S/4 – What about your output management?
Simplification Item: Output Management