[ADD] accounting: new shared accounts feature documentation

In 18.0 was the shared accounts feature added to Odoo but the documentation
doesn't contain any data related to it. This commit brings information about
said feature in the documentation.

task-4485674

Author: Megaaaaaa

content/applications/finance/accounting.rst

@@ -82,9 +82,12 @@ Multi-company
 =============
 
 Several companies can be managed within the same database. Each company has its :doc:`chart of
-accounts <accounting/get_started/chart_of_accounts>`, which is also useful to generate consolidation
-reports. Users can access several companies but can only work on a single company's accounting at a
-time.
+accounts <accounting/get_started/chart_of_accounts>`, but it is possible to share accounts
+between them for scenarios in which such a configuration would be required.
+
+.. seealso::
+   - :ref:`Shared Accounts Feature <coa_shared_accounts>`
+   - :doc:`Consolidation <accounting/get_started/consolidation>`
 
 Multi-currency environment
 ==========================

content/applications/finance/accounting/get_started.rst

@@ -179,6 +179,7 @@ Get started with Stripe and enable secure integrated credit and debit card payme
 .. seealso::
    * :doc:`bank`
    * :doc:`get_started/chart_of_accounts`
+   * :doc:`get_started/shared_accounts`
    * :doc:`bank/bank_synchronization`
    * :doc:`../fiscal_localizations`
    * `Odoo Tutorials: Accounting and Invoicing - Getting started [video]
@@ -189,6 +190,8 @@ Get started with Stripe and enable secure integrated credit and debit card payme
 
    get_started/cheat_sheet
    get_started/chart_of_accounts
+   get_started/shared_accounts
+   get_started/consolidation
    get_started/multi_currency
    get_started/avg_price_valuation
    get_started/tax_units

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

@@ -169,6 +169,15 @@ To do so, check the :guilabel:`Allow Reconciliation` box in the account's settin
 .. image:: chart_of_accounts/chart-of-accounts-reconciliation.png
    :alt: Allow reconciliation for accounts in Odoo Accounting
 
+.. _coa_shared_accounts:
+
+Shared Accounts
+---------------
+
+This :doc:`Shared Accounts <shared_accounts>` feature allows the creation of a single account for a
+specific purpose and sharing it between multiple companies. It is especially useful for
+multi-company environments where a similar account might be used across different companies.
+
 Deprecated
 ----------
 

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

@@ -0,0 +1,93 @@
+=============
+Consolidation
+=============
+
+The :doc:`Shared Accounts <shared_accounts>` feature can consolidate financial data for
+multi-company and multi-currency environments.
+
+This consolidation enables viewing a single :ref:`report <reporting>` by selecting the relevant
+company using the company selector in the top-right corner of the screen.
+
+Odoo uses the :abbr:`CTA (Cumulative Translation Adjustment)` system to translate all amounts into
+the selected company's currency by default for :ref:`multi-currency setups <multi_currency>`.
+
+.. _reporting:
+
+Reporting
+=========
+
+.. _report_consolidation:
+
+Report consolidation
+--------------------
+
+Consolidation sums up the values of the accounts shared between companies and allows for a **global
+view** of the whole group's financial situation.
+
+.. example::
+   The parent company has an invoice for 10.000€, while the child company has an invoice for
+   1.000€. Both companies share the same account for these invoices. The balance displayed on the
+   company report would be:
+   - 10.000€ for the parent company.
+   - 1.000€ for the child company.
+   - 11.000€ if both companies are selected in the company selector.
+
+.. _multi_currency:
+
+Multi-currency conversions
+==========================
+
+.. _cumulative_translation_adjustment:
+
+Cumulative Translation Adjustment
+---------------------------------
+
+In multi-currency environments, :abbr:`CTA (Cumulative Translation Adjustment)` uses the **selected
+company** currency for all the amounts in the report. CTA has three different calculation methods,
+chosen according to the **type of account** used in the transaction whose currency has to be
+changed.
+
+#. For **Equity** accounts, **except for retained earnings**, the CTA is calculated using the
+   historical rate, which is the rate at the time of the transaction.
+#. For **Income**, **Expense**, and **retained earnings** accounts, the CTA is calculated using the
+   average daily rate for the reported period.
+#. For other accounts, like **Assets** and **Liabilities** accounts, the CTA is calculated using
+   the closing rate, which is the last rate applied at the period’s closing date.
+
+This system may lead to unbalanced reports because the CTA can apply different rates for a
+transaction's payable and receivable, causing a difference in the total amount. This is normal and
+must be taken into account.
+
+.. note::
+   CTA can be disabled in the reports options under the :guilabel:`Currency Translation` label. Go
+   to the Accounting App. In the Configuration drop-down select :guilabel:`Accounting Reports` and
+   chose the report for which you wish to disable the CTA and head in the :guilabel:`Options` page
+   of the reprt's configuration. There, you can switch the :guilabel:`Currency Translation` option
+   to :guilabel:`Use the most recent rate at the date of the report`.
+
+.. _cumulative_translation_adjustment_examples:
+
+Examples
+--------
+
+The parent company is set to use EUR as its currency, while the child company uses USD. A single
+invoice for $10,000 is recorded in a shared account. The invoice was confirmed on January 1, 2025,
+when the exchange rate for **USD/EUR** was 1.0.
+The report was generated on December 31, 2025, when the exchange rate was 3.0. Between the invoice
+confirmation and the report generation, a rate of 2.0 was applied on July 1, 2025.
+Since the selected company uses euros, all amounts in the report are converted to euros based on
+the relevant exchange rates.
+
+- If the shared account is an **Equity** account, the CTA is calculated using the historical
+   exchange rate of 1.0. For an invoice of $10,000 issued on January 1, 2025, the Equity would be
+   €10,000.
+
+- If the shared account is an **Income** account, the CTA is calculated using the average daily
+   exchange rate for the reported period. Over the period, 181 days had a rate of 1.0 USD/EUR, 183
+   days had a rate of 2.0, and 1 day had a rate of 3.0. For an invoice of $10,000 issued on January
+   1, 2025, the average daily rate would be approximately 1.5068, resulting in an equity of about
+   €15,068.
+
+- If the shared account is an **Asset** account, the CTA is calculated using the closing exchange
+   rate of 3.0. For an invoice of $10,000 issued on January 1, 2025, the Asset would be €30,000,
+   resulting in a zero balance on the report.

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

@@ -0,0 +1,137 @@
+===============
+Shared Accounts
+===============
+
+In Odoo, accounts can be shared between multiple companies. This feature is particularly useful for
+businesses that operate under a **multi-company structure** and might benefit from a
+**unified chart of accounts**.
+
+Two ways are available to set up said feature: the :ref:`basic setup <setting_up_shared_accounts>`
+or using the :ref:`merge tool <merge_tool>`.
+
+The merging tool allows existing multi-company environments to use the new shared accounts feature.
+An :ref:`unmerge tool <unmerge_tool>` is also available to discontinue its use.
+
+This feature can also facilitate the :doc:`consolidation` of financial data across a multi-company
+environment, providing a **global view** of the financial situation for a group with child
+companies under a parent company.
+
+.. _shared_accounts_benefits:
+
+Benefits of Shared Accounts
+===========================
+
+1. Lighter load of accounts to handle
+-------------------------------------
+
+The main benefit of the shared accounts feature is to **reduce the amount of accounts** that have
+to be handled by the main accountant of a multi-company environment.
+
+.. example::
+   In environments with two companies using the same country’s generic chart of accounts, each
+   account used to appear twice. With the shared accounts feature, each account can now appear only
+   once.
+
+2. Simplified and Cleaner Reporting
+-----------------------------------
+
+The shared accounts feature **simplifies audit reports** while **keeping all data visible and
+accessible**, making the accounts easier to understand and manage.
+
+.. example::
+   In the balance sheet report, shared accounts between a company and its child company appear in a
+   single group, differentiated by the company using each account.
+
+3. Macro and Micro Management
+-----------------------------
+
+The shared accounts feature allows accountants to manage accounts at the appropriate level for each
+company. Main accountants can oversee the accounts of all child companies, clearly identifying each
+account’s purpose, even if the codes differ across companies. Meanwhile, child companies'
+accountants can manage their own accounts without worrying about their impact on other companies
+using the same account.
+
+.. example::
+   Even though the account is shared and exists as a single record in the database for all
+   companies, its code can be modified in each company without affecting the others, granting more
+   flexibility in account management.
+
+.. _setting_up_shared_accounts:
+
+Setting Up Shared Accounts
+==========================
+
+Enable Multi-Company
+--------------------
+
+To enable account sharing and the :doc:`multi-company </applications/general/multi_company>`
+feature, set up multiple companies in the database.
+
+Configure Shared Accounts
+-------------------------
+
+To configure a shared account, go to :menuselection:`Accounting --> Configuration --> Chart of
+Accounts` and click :guilabel:`View` on the account line. In the :guilabel:`Mapping` tab, enter
+a 6-digit code in the corresponding company :guilabel:`Code` column to share the account.
+
+The account will then be included in the :doc:`consolidation` process. To make it available for
+invoices in companies where a code has been configured, go to the :guilabel:`Accounting` tab and
+add a second company to the list of :guilabel:`Companies` that can use this account.
+
+.. _merge_tool:
+
+Merge Tool
+==========
+
+Use cases
+---------
+
+The merging tool simplifies creating shared accounts and is particularly useful when a
+**multi-company environment has been set up** with separate accounts that need to be merged.
+
+Steps
+-----
+
+To use the merge tool, select all the companies with an account that needs to be merged in the
+company selector in the top right corner of the screen.
+
+.. image:: shared_accounts/shared_accounts_merge_tool_select_companies.png
+   :alt: Selecting all companies that have accounts to be merged.
+
+Then, go to :menuselection:`Accounting --> Configuration --> Chart of Accounts` and select the
+accounts to merge. Click the :icon:`fa-cog` :guilabel:`Actions` menu and select :guilabel:`Merge
+accounts`.
+
+In the :guilabel:`Merge accounts window, enable the :guilabel:`Group by name?` option if needed and
+click :guilabel:`Merge`.
+
+The selected accounts are then merged into a single shared account, accessible by all the chosen
+companies, just as if the account had been created for one company and shared in the :ref:`basic
+setup <setting_up_shared_accounts>`.
+
+.. _unmerge_tool:
+
+Unmerge Tool
+============
+
+Use cases
+---------
+
+The unmerge tool simplifies stopping the sharing of specific accounts and allows **dissociating
+accounts from certain companies** without losing their data.
+
+Steps
+-----
+
+To unmerge accounts, select a company with a shared account in the top right corner of the screen.
+Then, go to :menuselection:`Accounting --> Configuration --> Chart of Accounts` and select the
+account to unmerge. Click the :icon:`fa-cog` :guilabel:`Actions` menu and select
+:guilabel:`Unmerge accounts`.
+
+An :guilabel: Odoo Warning` confirmation pop-up window will appear, listing how the accounts will
+be split.
+
+.. image:: shared_accounts/shared_accounts_unmerge_tool_confirmation_wizard.png
+   :alt: Confirmation wizard for the Unmerge Tool of the shared accounts feature.
+
+A new account linked to each company will be created for the previously shared account.