You can add the supplier reference in the purchase order line by following these steps:

1. Go to the "Purchases" app in Odoo and open the purchase order for which you want to add the supplier reference.

2. In the purchase order lines, click on the product field and select the product for which you want to add the supplier reference.

3. Once the product is selected, scroll down to the "Supplier Info" section and you will see the "Supplier Product Code" field. Enter the supplier reference in this field.

4. After you've added the supplier reference, you can save the purchase order.

5. If you want to view the supplier reference in the product form, you can do so by adding the field 'Supplier Product Code' to the form view of the product.

6. You can also access the supplier reference in the purchase order report. To do this you can add the field 'Supplier Product Code' to the report.

It's important to note that if the supplier reference is not filled in the purchase order line, the product reference will be used instead.

It's also important to note that if you want to see the supplier reference in the product form, you need to enable the 'Supplier Info' group on the product form view.

Hello Ahmed,
I did and it works !
Many thanks for your quick answer,
Thierry