If your organization is enabled for external tax calculation, you can validate the following addresses to check that they are recognized by the US Postal Service:
Validation is performed by an external system such as AvaTax. See Setting up External Tax Calculation for details of the setup required. If your organization is not enabled for external tax calculation, validating an address will have no effect and a message will be displayed telling you that external tax calculation is not enabled.
When you validate one of these addresses, if the original address is invalid (for example, because of formatting issues) an updated version of the address is proposed. You can then do one of the following:
If you edit an address after it has been validated, its Validated checkbox is deselected to indicate that the latest address has not been validated.