[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

content/applications/finance/accounting.rst

@@ -82,9 +82,13 @@ 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. Users can then
+access several companies but can only work on a single company's accounting at a time.
+
+.. 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/consolidation`
    * :doc:`bank/bank_synchronization`
    * :doc:`../fiscal_localizations`
    * `Odoo Tutorials: Accounting and Invoicing - Getting started [video]
@@ -189,6 +190,7 @@ Get started with Stripe and enable secure integrated credit and debit card payme
 
    get_started/cheat_sheet
    get_started/chart_of_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 **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 +1,139 @@
+=============
+Consolidation
+=============
+
+Imagine you have **several separate companies**, each with its own books. Consolidation lets you
+combine their financial data into **a single unified view** giving you a "fair image" of the entire
+group's financial health.
+
+In essence, consolidation in Odoo helps you gain a clear, comprehensive view of your group's
+financial performance by combining data from multiple companies.
+
+How it Works in Odoo
+====================
+
+**Several tools** combined together will contribute to the construction of your financial
+consolidation:
+
+#. **Account Mapping:** First, you can map similar accounts from different companies together. This
+   allows Odoo to combine them correctly in your consolidated reports.
+
+#. **Multi-Ledgers:** Ledgers are fundamental to the process of consolidation. They can either be:
+
+   - *Regular Ledgers:* Each of your companies has its own standard accounting ledger where all the
+     regular day--to-day transactions are recorded.
+
+   - *Consolidation Adjustments:* Each company also has special "MISC" journal just for
+     consolidation adjustments. This is where you make any tweaks needed to get everything to line
+     up correctly for the consolidation view.
+
+   - *Multi-Ledgers for Exclusion:* For each company, you can create a special multi-ledger which
+     excludes that company's consolidation adjustment journal. This gives you a clear picture of
+     the company's finances before consolidation adjustments are applied.
+
+   - *Multi-Ledger for Consolidation:* The company doing the actual consolidation also has a
+     special multi-ledger. This one includes all the other companies' consolidation adjustments
+     journals (the ones excluded from their own ledgers). This lets you see the total impact of all
+     the adjustments.
+
+#. **Multi-Company Selector:** To see the consolidated view, you'll use the multi-company selector.
+   Select the consolidating company as your current company, and then make the other companies
+   visible in the selector. This allows you to see all the journal items from the consolidating
+   company's perspective.
+
+#. **Horizontal Groups:** Odoo's reporting tools let you combine those multi-ledgers and use
+   horizontal groups to see the consolidated Balance Sheet or P&L. You can eve see how much each
+   company contributes to the overall consolidated figures.
+
+   .. important::
+      When you open financial reports, they usually default to a statutory view, meaning they use
+      the company's regular ledger (including its consolidation adjustment). To see the full
+      consolidation picture, you need to **make sure to select the multi-ledger** that includes all
+      the consolidation adjustments.
+
+#. **Group bys:** You can group by company, account, or any other dimension you want to see in your
+   consolidated reports.
+
+#. **Cumulative Translation Adjustments:** When consolidating companies with different currencies,
+   Odoo handles the translation.
+
+   - *Equity accounts:* Use the historical exchange rate.
+
+   - *Profit & Loss (P&L) accounts:* Use the average exchange rate.
+
+   - *Balance sheet accounts (excluding equity):* Use the closing exchange rate.
+
+   .. important::
+      The rates used are the ones from the running company.
+
+#. **Multi-Company Selector:** To see the consolidated view, you'll use the multi-company selector.
+   Select the consolidating company as your current company, and then make the other companies
+   visible in the selector. This allows you to see all the journal items from the consolidating
+   company's perspective.
+
+Consolidating Companies vs. Branch Management
+=============================================
+
+Consolidating companies involves legally separate entities whereas branches are subdivisions of a
+single legal entity which often share the head office's resources (journals, taxes, accounts,
+fiscal positions) and are not consolidated in the same way.
+
+.. _merge_tool:
+
+Account Merging
+===============
+
+You can merge accounts to reduce the number of accounts and standardize them across companies. This
+is optional; consolidation works without it.
+
+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:: consolidation/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 directly created to be shared.
+
+.. _unmerge_tool:
+
+Account Unmerging
+=================
+
+You can also unmerge accounts if ever needed.
+
+.. warning::
+
+   Note that unmerging accounts **does not unmerge the chatters** of the accounts. Once merged, the
+   chatters are permanently merged.
+
+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:: consolidation/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.
+
+Possibility to Import the Mapping
+=================================
+
+You can also import the accounts mapping.