For this you want to create two server action. Setting->Technical->Actions->Server Actions. Create a new server action for leave request to manager Action name:leave_request_manager.

Object:Leave

Action type:Email

Condition:True

Email Address: object.employee_id.parent_id.work_email

Subject: Leave Request from [[ object.employee_id.name ]]

Message: Dear [[object.employee_id.parent_id.name]],

You have one Leave Request from [[ object.employee_id.name ]]. Kindly click the link below to validate the application form. Web: localhost:8069 or ipaddress:8069

Thank you.

Create a new server action for approve mail from manager.

Action name:leave_approval_manager.

Object:Leave

Action type:Email

Condition:True

Email Address: object.employee_id.work_email

Subject: Leave Approval of [[object.employee_id.name]]

Message: Dear [[object.employee_id.name]]

[[object.number_of_days_temp]] day(s) leave from '[[object.date_from]]' to '[[object.date_to]]' has been approved.

Thank You.

Action name:leave_refusal_manager.

Object:Leave

Action type:Email

Condition:True

Email Address: object.employee_id.work_email

Subject: Leave Refusal of [[object.employee_id.name]]

Message: Dear [[object.employee_id.name]]

[[object.number_of_days_temp]] day(s) leave from '[[object.date_from]]' to '[[object.date_to]]' has been refused.

Thank You.

Next step is you want to call these server actions from workflow.

Setting->Technical->Workflow->Workflow->hr.wkf.holidays

confirm->server action->leave_request_manager

validate->server action->leave_approval_manager

refuse->server action->leave_refusal_manager(Kind:Dummy in Workflow)

Thus you can configure it