Tax rates are defined on a Postal Code basis. To update tax rates, follow the procedure below.
Navigate to Admin > Sales > Postal Codes.
Export the postal codes that are to be updated. You can export a subset by using the search form at the top of the page. In the example below, only postal codes in the state of Wyoming are selected.
Edit the exported postal codes with a spreadsheet application and save (retaining the CSV format).
Ingest the edited postal codes file specifying Postal Codes as the ingestion type.
Note: ZIP Code is a US term. The more generic term, applicable to all countries and used by TitleLeaf, is Postal Code.