Automatic posting to vendor account (SAP EDI) in intercompany process

Hello members,

I have some doubt on the automatic posting to vendor account in intercompany process. Firstly output type RD04 is configured which will trigger an idoc from my intercompany billing type IV. Then what happens with this idoc?

Then from the incoming side for vendor account posting how does the incoming idoc for  incoming payments get triggered?

Please explain the link between these 2 processes and the flow of transactions.

Thanks & Regards.