What is the difference between Event-Triggered module and Business Workflow module?

Both modules are triggered by an event. Event Trigger modules are triggered by their configured Triggered points or called up from other modules.
The business workflow is triggered by the arrival of a Business workflow requisition message. When a message arrives, the Business workflow module is triggered and uses the incoming message to process and then send a response. The Business Workflow module can be triggered from outside of Automation, such as from an HMI screen, Excel or a webpage.