As required by law, Amazon collects and remits state sales tax on all taxable marketplace sales shipped to certain states. You can find the specific states here: https://www.amazon.com/gp/help/customer/display.html?nodeId=202211260
FarApp automatically detects when Amazon has already collected and remitted tax for an order. FarApp then posts the order to Netsuite with a tax rate of 0.00. You can still view the tax amount in FarApp by selecting 'Edit' under the Action button on the far right of the order on the Orders page.