How to configure a service task as an external task in Camunda BPM?
Take a look in the service task documentation.
Here is an extract of the documentation to configure an service task as external.
To declare a Service Task to be handled externally, the attribute
camunda:type
can be set to external and the attributecamunda:topic
specifies the external task’s topic. For example, the following XML snippet defines an external Service Task with topic ShipmentProcessing:<serviceTask id="anExternalServiceTask" camunda:type="external" camunda:topic="ShipmentProcessing" />
For more information also read the external task user guide