Hi @CSLTGUPTAA,
By default, it will take email header parameters configured in the deployment wizard. If you want to use the different email headers than the default one then follow the below steps.
1. Go to Administration>Campaign Management>Technical delivery templates & duplicate the native template(Send an alert to workflow task assignees)
2. Change the email header details & save.
3. In Alert activity(Advanced parameters), change the delivery templates from native template to custom created template

Regards,
Amit