Hi Ravi,
I can give some basic information for Inbound & Outbound processing
Inbound: Data is sent to our through Gateway Services->TN->Mapping->Send to internal systems
Outbound:Internal Systems sent data->Map to required format(EDI/EDIFACT)->TN->Delivery as defined.
Note: It’s not always same way, different clients have there standars in implementation. But above is common thing which can see with most of clients.
Refer EDI Module Concepts guide
#edi#Integration-Server-and-ESB#webMethods