Customize approval request email from iProcurement

We have a request to customize approval request email contents from iProcurement, for both requisition approval email notification and po approval email notification, by adding data such as GL accounts and project # to the email, probably on line details. I read some notes about using Oracle BPM to customize email notification, but we don't have BPM installed.

Below is an example of  our email notification received by approvers from iProcurement, we want to add GL account and Project # to the email.

Could someone help to point out  detailed steps to implement this request ?

Thanks