From InfiniteERP Wiki
Each tax rate in Openbravo is a combination of different variables such as the tax category, the rate and the business partner tax category among others.
If all those variables are properly setup the correct tax rate is automatically filled in every business transaction.
Tax rate window allows to create as many tax rates as required.
Tax zone defines the origin country/region and destination country/region where a given tax rate applies,
for those case where it is not enough to define only one "Origin" Country/Region and only one "Destination" Country/Region at header level
Tax rates can be translated to any language required.
Accounting tab allows to configure the account to be used while posting tax rate transactions to the general ledger.
Full list of Tax Rate window fields and their descriptions is available in the Tax Rate Screen Reference.