show weight in shipping/invoice

As the title

How to show total weight of order in shipping invoice or invoice?

i did found previous related post but it sperated into too much post and i lost in the end

could you teach us the code and file to do the modification?

Hi,

There is no thread about that as far as I know.
You will have to recalculate the weight of the products of the order by loading the products information from the database, summing everything up and displaying it in the "invoice" file of the "order" view via the menu Display>Views.
It's more than a few lines of code and will require real development so I suggest that you hire a developer in order to add that.