Only a tax rule consistent with the legislation and group of the company associated with the site can be entered.The general principles linked to the multi-legislation setup aredetailed Here.
From this field, you can:
If this information is modified during the creation of the order or on its duplication and if the order lines exist, a question will be posed to the user about whether to re-calculate the prices and discounts for the order lines, namely when the price lists are expressed including taxes. When the order is created, this information is no longer accessible.
Inter-company specificities: In the case of an inter-company or inter-site order, the tax rule entered in the generated sales order is initialized with the tax rule of the customer associated with the purchase site.