You need to use the online reporting portal by clicking on the 'Reporting' button on the top panel
Once in the portal, navigate to the 'Reports' section along the left side of the screen and browse to the Finance folder
Run Sales Tax Summary or Sales Tax by Transaction report which would have dedicated columns for each tax code in the system.
Before checking these reports especially the Summary one please double check what is the method of tax calculation for your company; you can check it in WS - File - Configuration - Modules - Sales under part 'Tax calculation: Applied Before Discount/After discount'. If the Before discount is set, the tax will be always applied to the regular price regardless of discounts applied even if it is -100% price. If Including discount is selected the tax will always be applied to the final price of an item. Correspondingly, the Summary report column that stands for tax calculation basis is Total Unit Price if Before Discount method is set; if Including Discount is set, the tax is calculated based on Total Ext Price.
NOTE: during a wide range of dates the changes might be applied - the tax calculation method could have been switched, certain products could have been deactivated/made taxable/non-taxable. Please take these details into consideration and be able to track all changes in your product catalogue and POS configuration for a successful tax accounting procedure.