The ServiceTask node is a task type node, which is used for event calls on business functions. When the process flows to this node, it will call the external event bound to this node, and then automatically flow to the next node of the process. The process design diagram is shown below. The graphic node "Service" is a service node type.

On the Service node properties, you can define the specific information of the call event. The trigger position and expression are used to specifically describe the information of the event to be called and executed.