[ADD] accounting/electronic_invoicing: peppol backport

Since some customers can not upgrade in time before Peppol becomes mandatory
we backported the `account_peppol` module to 16.0.

This commit adds documentation on how to configure and use Peppol
(by backporting the 17.0 documentation).

task-4925169

closes #14876

Signed-off-by: Xavier Platteau (xpl) <xpl@odoo.com>

Author: svfu-odoo

content/applications/finance/accounting/customer_invoices/electronic_invoicing.rst

@@ -22,7 +22,7 @@ Odoo supports, among others, the following formats.
      - Applicability
    * - Factur-X (PDF/A-3)
      - For French and German companies
-   * - Peppol BIS Billing 3.0 (UBL)
+   * - Peppol BIS Billing 3.0 (UBL BIS Billing 3.0)
      - For companies whose countries are part of the `EAS list
        <https://docs.peppol.eu/poacc/billing/3.0/codelist/eas/>`_
    * - E-FFF
@@ -51,6 +51,8 @@ Odoo supports, among others, the following formats.
      - For Singaporean companies
    * - A-NZ BIS Billing 3.0
      - For Australian/New Zealand companies
+   * - Peppol
+     - For :ref:`Peppol<e-invoicing/peppol>`
 
 .. seealso::
    :ref:`fiscal_localizations/packages`
@@ -81,3 +83,174 @@ visible in the attachment section, or embedded in the PDF.
      Information`.
    - Odoo supports the **Peppol BIS Billing 3.0** format that can be used via existing access
      points.
+
+.. _e-invoicing/peppol:
+
+Peppol
+======
+
+The `Peppol <https://peppol.org/about/>`_ network ensures the exchange of documents and information
+between companies and governmental authorities. It is primarily used for electronic invoicing, and
+its access points (connectors to the Peppol network) allow companies to send electronic documents
+such as customer invoices and credit notes and receive documents like vendor bills and refunds.
+
+In this case, Odoo acts as both an **access point** and an :abbr:`SMP (Service Metadata Publisher)`
+and enables electronic invoicing transactions without the need to send invoices or bills by email or
+post.
+
+.. note::
+   - Make sure to :ref:`install <general/install>` the :guilabel:`Peppol` module (`account_peppol`).
+   - Peppol registration is **free** and available in Odoo Community.
+   - Supported formats for sending documents include **BIS Billing 3.0, XRechnung CIUS, and
+     NLCIUS**.
+   - | The following **countries** are eligible for **Peppol registration in Odoo**:
+     | Andorra, Albania, Austria, Bosnia and Herzegovina, Belgium, Bulgaria, Switzerland, Cyprus,
+       Czech Republic, Germany, Denmark, Estonia, Spain, Finland, France, United Kingdom, Greece,
+       Croatia, Hungary, Ireland, Iceland, Italy, Liechtenstein, Lithuania, Luxembourg, Latvia,
+       Monaco, Montenegro, North Macedonia, Malta, Netherlands, Norway, Poland, Portugal, Romania,
+       Serbia, Sweden, Slovenia, Slovakia, San Marino, Turkey, Holy See (Vatican City State)
+
+.. _e-invoicing/peppol-registration:
+
+Registration
+------------
+
+To register on Peppol, go to :menuselection:`Accounting --> Configuration --> Settings`, scroll
+to the :guilabel:`PEPPOL Electronic Document Invoicing` section, and fill in the following
+information:
+
+- :guilabel:`Peppol EAS`: Peppol Electronic Address Scheme, which usually depends on the
+  company's country. This field is often prefilled with your country's most commonly used EAS
+  code. For example, the preferred EAS code for most companies in Belgium is `0208`.
+- :guilabel:`Peppol Endpoint`: usually a Company Registry number or a VAT number
+- :guilabel:`Mobile Number`, including the country code (e.g., `+32` in Belgium)
+- :guilabel:`Primary contact email`
+
+   .. seealso::
+      - `Peppol EAS - European Commision <https://ec.europa.eu/digital-building-blocks/wikis/display/DIGITAL/Code+lists/>`_
+      - `Peppol endpoint - OpenPeppol eDEC Code Lists <https://docs.peppol.eu/edelivery/codelists/>`_
+        (open the "Participant Identifier Schemes" as HTML page)
+
+#. Click :guilabel:`Validate registration`.
+
+#. The registration should be automatically activated, and the :guilabel:`Application status`
+   should be updated within a day.
+
+#. Select another purchase journal in the :guilabel:`Incoming Invoices Journal` field if necessary.
+
+All invoices can then be sent directly using Peppol.
+
+.. note::
+   - To update the :guilabel:`Primary contact email`, modify it and click :guilabel:`Update contact
+     details`.
+   - If you are using an access point from a previous provider, make sure to deregister from it
+     first, then register with your new access point, unless it's Hermes (BOSA). If using Hermes
+     (BOSA), no action is needed; the migration is handled automatically.
+
+.. tip::
+   - To manually trigger the scheduled action used to check the Peppol registration status, enable
+     :ref:`developer mode <developer-mode>`, open the Settings app, go to :menuselection:`Settings
+     --> Technical --> Scheduled actions`, and search for :guilabel:`Peppol: update participant
+     status`. Open the scheduled action, then click :guilabel:`Run Manually`.
+   - To try Peppol without sending real data, use the demo mode by setting the
+     :guilabel:`account_edi_proxy_client.demo` system parameter to `demo`. This has to be done
+     before clicking :guilabel:`Validate registration`.
+   - For advanced testing on Peppol's dedicated test network, use the test mode by setting the
+     :guilabel:`account_edi_proxy_client.demo` system parameter to `test`. This option is intended for
+     experienced users only. This has to be done before clicking :guilabel:`Validate registration`.
+
+.. _e-invoicing/contact-verification:
+
+Contact verification
+--------------------
+
+Before sending an invoice to a contact using Peppol, make sure the contact is registered as a Peppol
+participant. To do so, follow these steps:
+
+#. Go to :menuselection:`Accounting --> Customers --> Customers` and access the customer's form.
+#. In the :guilabel:`Accounting tab`, check the following information in the :guilabel:`Electronic
+   Invoicing` section:
+
+   - :guilabel:`Format`: :guilabel:`BIS Billing 3.0`, :guilabel:`XRechnung CIUS`, or
+     :guilabel:`NLCIUS`.
+   - :guilabel:`Peppol e-address (EAS)`: Select the relevant EAS code in the dropdown list.
+   - :guilabel:`Peppol Endpoint`: Enter the customer's endpoint identifier.
+
+#. Click :guilabel:`Verify`. Its :guilabel:`Peppol endpoint validity` is marked as :guilabel:`Valid`
+   if the contact is found on the Peppol network.
+
+.. important::
+   While Odoo prefills both the EAS code and the endpoint number based on the information available
+   for a contact, verifying these details with the contact is recommended.
+
+.. _e-invoicing/send-invoices:
+
+Send invoices
+-------------
+
+To generate Peppol documents for invoices of a journal
+:ref:`enable the EDI format called 'Peppol' on the journal<e-invoicing/configuration>`.
+This should have happened automatically for countries in which Peppol is used by installing the module.
+Then confirming an invoice will generate Peppol a document in the format selected on the partner
+during the :ref:`contact verification<e-invoicing/contact-verification>`.
+
+
+Posted invoices to be sent via Peppol are marked as :guilabel:`Ready to send` in the invoice's
+:guilabel:`PEPPOL status` field.
+
+.. note::
+   All invoices that are ready to be sent via Peppol can be viewed in the following ways:
+
+   - In the :guilabel:`Invoices` list view, use the :icon:`oi-settings-adjust` (:guilabel:`adjust
+     settings`) button to add the :guilabel:`PEPPOL status` column or apply the :guilabel:`Peppol
+     Ready` filter in the search bar.
+   - In the Accounting dashboard, click :guilabel:`Peppol ready invoices` on the relevant sales
+     journal.
+
+To send the invoice to the customer via Peppol, click :guilabel:`Send & Print` on the confirmed
+invoice form. In the :guilabel:`Send` window, enable  :guilabel:`Send via PEPPOL` options, then click
+:guilabel:`Send & Print` (or :guilabel:`Send` or :guilabel:`Send (Peppol)` or :guilabel:`Print`
+depending on which of the :guilabel:`Print` and :guilabel:`Email` options are selected).
+
+.. tip::
+   Multiple invoices can also be sent in batches via Peppol by using the :guilabel:`Invoices`
+   list view.
+
+Once the invoices are sent via Peppol, their :guilabel:`PEPPOL status` is changed to
+:guilabel:`Processing`.
+
+The status is updated to :guilabel:`Done` once the invoices have been successfully delivered to the
+contact's access point.
+
+.. tip::
+   To manually trigger the scheduled action used to check the invoices' status, go to the
+   Accounting dashboard and click :guilabel:`Fetch Peppol invoice status` on the corresponding sales
+   journal.
+
+.. _e-invoicing/receive-vendor-bills:
+
+Receive vendor bills
+--------------------
+
+New documents received via Peppol are checked multiple times a day. Received documents are
+automatically imported into the purchase journal set in the :guilabel:`PEPPOL Electronic Document
+Invoicing` section, and corresponding vendor bills are created as drafts and appear in the vendor
+bills list view.
+
+.. tip::
+   To manually trigger the scheduled action to retrieve incoming Peppol documents, go to the
+   Accounting dashboard and click :guilabel:`Fetch from Peppol` on the main Peppol purchase journal.
+
+.. _e-invoicing/peppol-deregister:
+
+Peppol deregistration from Odoo
+-------------------------------
+
+Only one Peppol receiver registration can be active for each Peppol endpoint identifier at a time.
+To stop using Odoo as the Peppol access point, e.g., to switch to another provider or reconfigure
+the registration for a new database, you must first deregister from Peppol. To do so, go to
+:menuselection:`Accounting --> Configuration --> Settings`, scroll down to the :guilabel:`PEPPOL
+Electronic Invoicing` section, and click :guilabel:`Deregister from Peppol`.
+
+Once removed, the Peppol registration is deleted from the database, and documents can no longer be
+sent or received via Peppol in Odoo.