Customization of prestashop 1.6 delivery slip

Hi,

Goal of this project is to change delivery slip content, code modificaion it should be comptabile prestashop 1.6.13 and 1.6.24

2 changes:
- the "delivery number" field by shoud be replaced an "order number" field (see picture attached)
- Customer message provided in order should be added at the bottom of the delivery slip (see picture attached)

Can be directly in prestashop files if faster
Thanks