thank you yahoo

this is very good point you told and this showing in the delivery slip form
but when I want to print the delivery I have same problem

can you please tell me what should I have to do?

HI
I did not get any error but description is not showing

I just figured out this answer today as I had the same question. I utilize a lot of custom descriptions so that I do not have so many products.

This answer is using Studio in Odoo 18:

1. Open up a delivery transaction. 
2. Click the studio button in the top right.
3. Click the area with the product information columns.
4. Click edit list view.
5. Click and drag a new related field and place it as a new column.
6. Field properties window will pop up, search for and select "Sales Description".

I hope this has been helpful!

edit** I just found out, this does not add the description to the pdf report, only to the view within the delivery.