I tried to get current user using session and authorizable. But none of them giving the current user who invokes the particular step.
Is there any other way to get the current user details ?
You can use getInitiator() method of Workflow API to get the user ID of the user who started the workflow.
Refer https://helpx.adobe.com/experience-manager/6-3/sites/developing/using/reference-materials/javadoc/co... API to get to know more about this particular method.
Returns the initiator of the Workflow instance.
The user who initiated the Workflow.
Hope it helps!