The CSI Tax integration makes use of the taxation service bureau APIs to calculate the appropriate taxes per invoice line item during the invoice generation process and add them to the invoice.
To configure, head over to the Relationship you are configuring Invoicing for and ensure that the Zip Code in its Relationship Info. Once a Zip Code is saved you'll be able to select CSI from the Taxation drop-down found in the same Relationship's Invoice tab. Over on the top-right side:
As balances are updated in the platform, a taxation table is updated with the interstate, intrastate and indeterminate information for when invoices are generated.
Please note that only the total tax is displayed on the invoice.