[ADD] Thailand localisation Documentation

- Added Thailand localisation documentation as it not exist before.
Features were pushed to Odoo 16 already

closes #5483

Signed-off-by: Xavier Platteau (xpl) <[email protected]>

Author: “tap-odoo”~

content/applications/finance/fiscal_localizations.rst

@@ -122,7 +122,7 @@ available on Odoo.
 - Sweden - Accounting
 - :doc:`Switzerland - Accounting <fiscal_localizations/switzerland>`
 - Taiwan - Accounting
-- Thailand - Accounting
+- :doc:`Thailand - Accounting <fiscal_localizations/thailand>`
 - Turkey - Accounting
 - :doc:`United Arab Emirates - Accounting <fiscal_localizations/united_arab_emirates>`
 - :doc:`UK - Accounting <fiscal_localizations/united_kingdom>`
@@ -158,5 +158,6 @@ available on Odoo.
    fiscal_localizations/saudi_arabia
    fiscal_localizations/spain
    fiscal_localizations/switzerland
+   fiscal_localizations/thailand
    fiscal_localizations/united_arab_emirates
    fiscal_localizations/united_kingdom

content/applications/finance/fiscal_localizations/thailand.rst

@@ -0,0 +1,111 @@
+========
+Thailand
+========
+
+Configuration
+=============
+
+:ref:`Install <general/install>` the :guilabel:`🇹🇭 Thailand` localization package to get all the
+features of the Thai localization:
+
+.. list-table::
+   :header-rows: 1
+
+   * - Name
+     - Technical name
+     - Description
+   * - :guilabel:`Thailand - Accounting`
+     - `l10n_th`
+     - Default :ref:`fiscal localization package <fiscal_localizations/packages>`
+   * - :guilabel:`Thailand - Accounting Reports`
+     - `l10n_th_reports`
+     - Country-specific accounting reports
+
+.. image:: thailand/thailand-modules.png
+   :alt: Thailand localization modules
+
+Chart of accounts and taxes
+===========================
+
+Odoo's fiscal localization package for Thailand includes the following taxes:
+
+- VAT 7%
+- VAT-exempted
+- Withholding tax
+- Withholding income tax
+
+Tax report
+==========
+
+Odoo allows users to generate Excel files to submit their VAT to the **Revenue Department** of
+Thailand.
+
+Sales and purchase tax report
+-----------------------------
+
+To generate a sales and purchase tax report, go to :menuselection:`Accounting --> Reporting --> Tax
+Report`. Select a specific time or time range on the tax report, and click
+:guilabel:`VAT-202-01 (xlsx)` for purchase tax and :guilabel:`VAT-202-02 (xlsx)` for sales tax.
+
+.. image:: thailand/thailand-tax-report.png
+   :alt: Thai purchase and sales taxes reports
+
+Withholding PND tax report
+--------------------------
+
+PND report data displays the summarized amounts of the applicable **withholding corporate income
+tax returns (domestic)** from vendor bills under the :guilabel:`PND53 (TH)` and
+:guilabel:`PND3 (TH)` tax reports. It is installed by default with the Thai localization.
+
+.. image:: thailand/thailand-pnd-report.png
+   :alt: PND tax reports
+
+.. note::
+   Withholding corporate income tax returns (domestic) is the tax used in case the company has
+   withheld the tax from “**Personal (PND3)**” or “**Corporate (PND53)**” services provided such as
+   rental, hiring, transportation, insurance, management fee, consulting, etc.
+
+The PND tax report allows users to generate a CSV file for bills to upload on the
+`RDprep for Thailand e-Filling application <https://efiling.rd.go.th/rd-cms/>`_.
+
+To generate a PND CSV file, go to :menuselection:`Accounting --> Reporting --> Tax Report`, select a
+specific time or time range on the tax report, and click :guilabel:`PND3` or :guilabel:`PND53`.
+
+This generates the :file:`Tax Report PND3.csv` and :file:`Tax Report PND53.csv` files that lists all
+the vendor bill lines with the applicable withholding tax.
+
+.. image:: thailand/thailand-pnd3-pnd53.png
+   :alt: PND3 and PND53 CSV files
+
+.. warning::
+   Odoo cannot generate the PND or PDF report or **withholding tax certificate** directly. The
+   generated :file:`Tax Report PND3.csv` and :file:`Tax Report PND53.csv` files must be exported
+   to an external tool to convert them into a **withholding PND** report or a **PDF** file.
+
+Tax invoice
+===========
+
+The **tax invoice PDF** report can be generated from Odoo through the **Invoicing** module. Users
+have the  option to print PDF reports for normal invoices and tax invoices. To print out
+**tax invoices**, users can click on :guilabel:`Print Invoices` in Odoo. Regular invoices can be
+printed as **commercial invoices** by clicking on :menuselection:`Cog button (⚙️) --> Print -->
+Commercial Invoice`.
+
+.. image:: thailand/thailand-tax-invoice.png
+   :alt: Commercial invoice printing
+
+Headquarter/Branch number settings
+----------------------------------
+
+You can inform a company's **Headquarters** and **Branch number** in the **Contacts** app. Once
+in the app, open the **contact form** of the company and under the :guilabel:`Sales & Purchase` tab:
+
+- If the contact is identified as a branch, input the **Branch number** in the
+  :guilabel:`Company ID` field.
+- If the contact is a **Headquarters**, leave the :guilabel:`Company ID` field **blank**.
+
+.. image:: thailand/thailand-contact.png
+   :alt: Company Headquarter/Branch number
+
+.. tip::
+   This information is used in the **tax invoice** PDF report and PND **tax report** export.