The HS Code is used by customs authorities around the world to identify products when processing goods for import or export. In the United States, the HS Code is often referred to as the Schedule B number.
Nerd Alert: Including the HS Code on your commercial invoice is optional but it is recommended. It can be entered in the Product details:
Entering the correct HS code will help customs classify your products correctly, otherwise they're relying on the product description that you've entered to find the right classification. Unfortunately, if no HS code is entered it is very hard to appeal entries that have been classified incorrectly.
To find the code for the item(s) you are shipping:
Importing to or from the USA: Schedule B Search Engine
Importing to or from Canada: Canada Tariff Finder
As the shipper, you are responsible for ensuring that all items within your shipment comply with applicable international treaties, laws, regulations, or requirements.