magento/magento2/blob/2.1.3/app/code/Magento/Tax/README.md#L5-L19


The Magento_Tax module includes the following:
* configuration of the tax rates and rules to apply
* configuration of tax classes that apply to:
** taxation on products
** taxation on shipping charges
** taxation on gift options (example: gift wrapping)
* specification whether the consumption tax is "sales & use" (typically product prices are loaded without any tax) or "VAT" (typically product prices are loaded including tax)
* specification of whether the tax total line can be toggled to display the tax details/subtotals
* display of prices (presented with tax, without tax, or both with and without)


The Magento_Tax module also handles special cases when computing tax, such as:
* determining the tax on an individual item (for example, one that is being returned) when the original tax has been computed on the entire shopping cart
** example country: United States
* being able to handle 2 or more tax rates that are applied separately (examples include a "luxury tax" on exclusive items)
* being able to handle a subsequent tax rate that is applied after a previous one is applied (a "tax on tax" situation, which recently was a part of Canadian tax law)