Two questions regarding sales:

We invoice our customer for shipping/courier charge, should this be classified as sales?

We invoice our customer for boxes/cartons supplied by us, should this be classified as sales?

Thank you!

I would keep them separate so that you can track sales of your product vs the other 2.
I would track all 3, easily enough with computers.
Also, part of how you track them depends on whether you are in a state that requires sales tax on shipping or not. If you are in such a state, they are going to want tax on the item, materials, and shipping, since you charge the customer directly for the materials. I'd track the total being taxed (4th category) or you will have a rounding problem breaking down the tax.

No. All packing charges and freight charges for out words are treated as an expenses.

I forgot to ask what country you are in.
I wasn't saying that materials and postage aren't expenses...