Send Task
In descriptive models, a Send task sends a message flow immediately and then completes. It performs no other actions. It is effectively the same as a throwing Message intermediate event.
In executable models, a Send task does the same thing, but the message sent is one defined by a service operation in the Operation Libtary. Thus it is similar to a Service task, where the invoked service returns a synchronous response, except that a Send task is asynchronous.
The Attributes/Send Task context menu action lets you select the service operation from the Operation Library and its corresponding input message, and map process variables to it.