Postal Code

Go to System → Settings → Store Details

The ZIP or postal code of your store's location. This information is displayed on the Contact Us page but currently doesn't affect product tax calculations. Guest customers are affected by the Store’s Country and State values.

Please note some extensions like https://abantecart.atlassian.net/wiki/spaces/AD/pages/17236073, Avatax, USPS may have own setting for “origin” or “shipping from” zip code