I need a prestashop expert

Hello,
Our wine business is using a prestashop platform, we have constant modifications to make to offer the best tool.
As a first step : Our prestashop is a b to b shop so our customers have the option to pay latter once the have made an order. We would like that once they make their order it appears on the mail they receive as " unpayed "
You will find an example in attachment,


Thank you for your answer,