[ADD] accounting/l10n: new localization page for India

closes odoo/documentation#1940

Signed-off-by: Castillo Jonathan (jcs) <jcs@odoo.com>
Co-authored-by: Jonathan Castillo <jcs@odoo.com>

content/applications/finance/accounting/fiscal_localizations/localizations.rst

@@ -15,6 +15,7 @@ Localizations
    localizations/egypt
    localizations/france
    localizations/germany
+   localizations/india
    localizations/indonesia
    localizations/italy
    localizations/italy_IT

content/applications/finance/accounting/fiscal_localizations/localizations/india.rst

@@ -0,0 +1,189 @@
+=====
+India
+=====
+
+.. _india/installation:
+
+Installation
+============
+
+:ref:`Install <general/install>` the following modules to get all the features of the Indian
+localization:
+
+.. list-table::
+   :header-rows: 1
+
+   * - Name
+     - Technical name
+     - Description
+   * - :guilabel:`Indian - Accounting`
+     - `l10n_in`
+     - Default :doc:`fiscal localization package <../overview/fiscal_localization_packages>`
+   * - :guilabel:`Indian E-invoice Integration`
+     - `l10n_in_edi`
+     - :ref:`Indian e-invoicing integration <india/e-invoicing>`
+
+.. _india/e-invoicing:
+
+Indian e-invoicing
+==================
+
+Odoo is compliant with the **Indian Good and Services Tax (GST) e-Invoice system** requirements.
+
+.. important::
+   Indian e-invoicing is available from Odoo 15.0. If needed, :doc:`upgrade
+   </administration/upgrade>` your database.
+
+.. _india/e-invoicing-api:
+
+Registration on your NIC e-Invoice web portal
+---------------------------------------------
+
+You must register on the **NIC e-Invoice** web portal to get your **API credentials**. You need
+these credentials to :ref:`configure your Odoo Accounting app <india/e-invoicing-configuration>`.
+
+#. Login to the NIC e-Invoice web portal on - https://einvoice1.gst.gov.in/ by clicking on
+   :guilabel:`Login` and entering your :guilabel:`Username` and :guilabel:`Password`.
+
+   .. note::
+      If you have already registered on the NIC Eway Bill Production portal, then you can use the
+      same login credentials here.
+
+   .. image:: india/e-invoice-system-login.png
+      :align: center
+      :alt: Register Odoo ERP system on e-invoice web portal
+
+#. From your dashboard, go to :menuselection:`API Registration --> User Credentials --> Create API
+   User`.
+
+   .. image:: india/e-invoice-create-api-user.png
+      :align: center
+      :alt: Click on User Credentials and Create API User
+
+#. After that, you receive an :abbr:`OTP (one-time password)` code to your registered mobile number.
+#. Enter the OTP code and click on :guilabel:`Verify OTP`.
+
+   .. image:: india/trigger-otp.png
+      :align: center
+      :alt: Trigger an OTP to your registerd phone number
+
+#. Select :guilabel:`Through GSP` in the first field, select :guilabel:`Tera Software Limited`
+   as your GSP, and type in a :guilabel:`Username` and :guilabel:`Password` for your API.
+
+   .. image:: india/submit-api-registration-details.png
+      :align: center
+      :alt: Submit API specific Username and Password
+
+#. Click on :guilabel:`Submit`.
+
+.. _india/e-invoicing-configuration:
+
+Configuration on Odoo
+---------------------
+
+To set up the e-invoice service, go to :menuselection:`Accounting --> Configuration --> Settings -->
+Indian Electronic Invoicing`, and enter the :guilabel:`Username` and :guilabel:`Password`.
+
+.. image:: india/e-invoice-setup.png
+   :align: center
+   :alt: Setup e-invoice service
+
+.. _india/e-invoicing-journals:
+
+Journals
+~~~~~~~~
+
+Your default *sales* journal should be already configured correctly. You can check it or configure
+other journals by going to :menuselection:`Accounting --> Configuration --> Journals`. Then, open
+your *sales* journal, and in the :guilabel:`Advanced Settings` tab, under :guilabel:`Electronic Data
+Interchange`, check :guilabel:`E-Invoice (IN)` and :guilabel:`Save`.
+
+.. image:: india/journal-configuration.png
+   :align: center
+   :alt: Journal configuration
+
+.. _india/e-invoicing-workflow:
+
+Workflow
+--------
+
+To start invoicing from Odoo, an invoice must be created using the standard invoicing flow, that is,
+either from a sales order or the invoice menu in the Accounting application.
+
+.. _india/invoice-validation:
+
+Invoice validation
+~~~~~~~~~~~~~~~~~~
+
+Once the invoice is validated, a confirmation message is displayed at the top.
+
+Odoo automatically uploads the JSON-signed file to the government portal after a while. If you want
+to process the invoice immediately, you can click on :guilabel:`Process Now`.
+
+.. image:: india/e-invoice-process.png
+   :align: center
+   :alt: Indian e-invoicing confirmation message: "The invoice will be processed asynchronously by
+         the following E-invoicing service : E-Invoice (IN)"
+
+.. note::
+   - You can find the JSON-signed file in the attached files, in the chatter.
+   - You can check the status of EDI with web-service under the :guilabel:`EDI Document` tab or the
+     :guilabel:`Electronic invoicing` field.
+
+.. _india/invoice-pdf-report:
+
+Invoice PDF Report
+~~~~~~~~~~~~~~~~~~
+
+Once the invoice is submitted and validated, you can print the invoice PDF report. The report
+includes the :abbr:`IRN (Invoice Reference Number)`, acknowledgment number and date, and QR code.
+They certify that the invoice is a valid fiscal document.
+
+.. image:: india/invoice-report.png
+   :align: center
+   :alt: IRN and QR code
+
+.. _india/edi-cancellation:
+
+EDI Cancellation
+~~~~~~~~~~~~~~~~
+
+If you want to cancel an e-invoice, go to the :guilabel:`Other info` tab of the invoice and fill out
+the :guilabel:`Cancel reason` and :guilabel:`Cancel remarks` fields. Then, click on
+:guilabel:`Request EDI cancellation`. The status of the :guilabel:`Electronic invoicing` field
+changes to :guilabel:`To Cancel`.
+
+.. image:: india/e-invoice-cancellation.png
+   :align: center
+   :alt: cancel reason and remarks
+
+.. note::
+   If you want to abort the cancellation before processing the invoice, then click on
+   :guilabel:`Call Off EDI Cancellation`.
+
+Once you request to cancel the e-invoice, Odoo automatically submits the JSON Signed file to the
+government portal. If you want to process the invoice immediately, you can process it by clicking on
+:guilabel:`Process Now`.
+
+.. _india/verify-e-invoice:
+
+Verify the e-invoice from the GST
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+After submitting an e-invoice, you can also verify the signed invoice from the GST e-Invoice system
+website.
+
+#. Download the JSON file from the attached files.
+#. Open the e-invoice portal: https://einvoice1.gst.gov.in/ and go to :menuselection:`Search -->
+   Verify Signed Invoice`.
+#. Select the JSON file and submit it.
+
+   .. image:: india/verify-invoice.png
+      :align: center
+      :alt: select the JSON file for verify invoice
+
+#. You can check the verified signed e-invoice here.
+
+   .. image:: india/signed-invoice.png
+      :align: center
+      :alt: verified e-invoice