Email templates allow you to personalise the emails sent to suppliers when PO statuses change. Some very basic templates are setup by default.
The shortcodes you can use in the emails are in the left-hand side column for easy reference.
There are boxes for Store, Supplier (vendor) and Order related tags.
The Order Status drop down box selects which email template you are working on. Simply change the order status to reload the page and work on the associated email template.
When you select Part Received, you will be editing the email template that is sent to suppliers when the PO status changes to Part Received.