If you need to To charge tax on a funnel/campaign you can do so by editing the funnel’s settings , go to the funnel Settings and open the Tax Profiles section.
...
...
Specify the Country, State (optional), and Tax Rate.
Include Tax in Final Price = Include tax in the product prices displayed to customers (such as a VAT). Do not include tax in the campaign product prices. Tax will be automatically added to the prices displayed on live pages.
Exclude Rebills = Do not charge tax on rebills
Customers from that region will now be charged the sales tax amount applied.