Hi,
In case of AEM 6.4 the default path for template used is /libs/settings/workflow/notification/email/tasks/created/en.txt [1].
You can make necessary modifications in the templates being used for sending emails, check below link for details around it if this supports your use case.
https://helpx.adobe.com/in/experience-manager/6-4/sites/administering/using/notification.html
Regards,
Sumeet Chawla.
[1]:
subject=${item.name}: Task Created1
header=-------------------------------------------------------------------------------------\n \
Task: ${item.name}\n \
Description: ${item.description}\n \
User: ${participant.name} (${participant.id})\n \
-------------------------------------------------------------------------------------\n\n
message=Content: ${host.prefix}${payload.path.open}\n
footer=\n \
-------------------------------------------------------------------------------------\n \
View the overview in your ${host.prefix}/aem/inbox\n \
-------------------------------------------------------------------------------------\n \
This is an automatically generated message. Please do not reply.