[ADD] accounting: VAT units

task-2557013

16.0: Line 36 = "Create" --> "New"

closes #4375

Signed-off-by: Aarab Tom (toaa) <toaa@odoo.com>

Author: toaa-odoo

content/applications/finance/accounting/get_started.rst

@@ -196,3 +196,4 @@ Send yourself a sample invoice by email to make sure everything is correctly con
    get_started/chart_of_accounts
    get_started/multi_currency
    get_started/avg_price_valuation
+   get_started/vat_units

content/applications/finance/accounting/get_started/vat_units.rst

@@ -0,0 +1,86 @@
+=========
+VAT units
+=========
+
+.. important::
+   This is only applicable to multi-company environments.
+
+A **VAT unit** is a group of VAT-taxable enterprises that are legally independent of each other but
+are closely linked financially, organizationally, and economically and therefore considered the same
+VAT-taxable enterprise. **VAT units** are not mandatory, but if created, constituent companies of
+the unit must belong to the same **country**, use the same **currency**, and one company must be
+designated as the **representative** company of the **VAT unit**. **VAT units** receive a specific
+**tax ID** intended only for **tax returns**. **Constituent** companies keep their **tax ID** used
+for **commercial purposes**.
+
+.. example::
+   Enterprise **A** owes €300.000,00 of VAT taxes and enterprise **B** can recover €280.000,00 of
+   VAT taxes. They form up as a **VAT unit** so that the two amounts balance out and must conjointly
+   only pay €20.000,00 of VAT taxes.
+
+Configuration
+=============
+
+To configure a **VAT unit**, go to :menuselection:`Settings --> General Settings`, scroll down to
+the :guilabel:`Companies` section, and click :guilabel:`Manage Companies`. Select the company to
+serve the **representative** role, and in the :guilabel:`General Information` tab, fill in the
+mandatory fields for the .XML export when exporting the **tax report**: :guilabel:`Company Name`,
+:guilabel:`Address`, :guilabel:`VAT`, :guilabel:`Currency`, :guilabel:`Phone`, and
+:guilabel:`Email`.
+
+.. image:: vat_units/general.png
+   :align: center
+   :alt: General information tab
+
+Then, click on the :guilabel:`VAT Units` tab, :guilabel:`Add a line`, and either select an existing
+**VAT unit**, or create a new one. Enter a **name** for the unit, :guilabel:`Country` of the
+constituent companies and tax report, the :guilabel:`Companies`, the :guilabel:`Main Company` that
+serves the **representative** role, and the :guilabel:`Tax ID` of the **VAT unit**.
+
+.. image:: vat_units/vat-unit.png
+   :align: center
+   :alt: VAT units tab
+
+Fiscal position
+---------------
+
+As transactions between constituents of the same **VAT unit** are not subject to VAT, it is possible
+to create a :doc:`tax mapping (fiscal position) <../taxes/fiscal_positions>` to avoid the
+application of VAT on inter-constituent transactions.
+
+Be sure a constituent company has been selected before, then go to :menuselection:`Accounting -->
+Configuration --> Fiscal Positions`, and :guilabel:`Create` a new **fiscal position**. Click the
+:guilabel:`Tax Mapping` tab, select the :guilabel:`Tax on Product` usually applied for
+**non-constituent** transactions, and in :guilabel:`Tax to Apply`, select the 0% tax to apply for
+**constituent** transactions.
+
+Do the same for the :guilabel:`Account Mapping` tab if required, and repeat this process for
+**each** constituent company on your database.
+
+.. Example::
+   Depending on your :doc:`localization package </applications/finance/fiscal_localizations>`, taxes
+   may vary from the screenshot displayed.
+
+   .. image:: vat_units/fiscal-positions.png
+      :align: center
+      :alt: Tax mapping of fiscal position for VAT unit
+
+Then, assign the fiscal position by opening the **Contacts** app. Search for a **constituent**
+company, and open the contact's **card**. Click the :guilabel:`Sales & Purchase` tab, and in the
+:guilabel:`Fiscal Position` field, input the **fiscal position** created for the **VAT unit**.
+Repeat the process for each **constituent** company card form, on each company database.
+
+.. seealso::
+   :doc:`../taxes/fiscal_positions`.
+
+Tax report
+==========
+
+The **representative** company can access the aggregated tax report of the **VAT unit** by going to
+:menuselection:`Accounting --> Reporting --> Tax Report`, and selecting the **VAT unit** in
+:guilabel:`Tax Unit`. This report contains the aggregated transactions of all **constituents** and
+the .XML export contains the name and VAT number of the **main** company.
+
+.. image:: vat_units/report.png
+   :align: center
+   :alt: VAT unit tax report