[ADD] subscriptions: add ecommerce configuration

closes odoo/documentation#4270

Signed-off-by: Melanie Nguyen (meng) <meng@odoo.com>

content/applications/sales/subscriptions.rst

@@ -4,20 +4,23 @@
 Subscriptions
 =============
 
-**Odoo Subscriptions** is used to run recurring businesses: :ref:`sell new contracts
-<subscriptions/quotations>`, :doc:`upsell customers <subscriptions/upselling>`, keep the churn under
-control, and :doc:`generate reports <subscriptions/reports>` on the main KPIs: MRR, ARR, retention,
-churn, upselling, etc.
+Odoo *Subscriptions* is used to run recurring businesses: :ref:`sell new contracts
+<subscriptions/quotations>`, :doc:`upsell customers </applications/sales/subscriptions/upselling>`,
+keep the churn under control, and :doc:`generate reports
+</applications/sales/subscriptions/reports>` on the main :abbr:`KPIs (Key Performance Indicators)`:
+:abbr:`MRR (Monthly Recurring Revenue)`, :abbr:`ARR (Annual Recurring Revenue)`, retention, churn,
+etc.
 
 .. seealso::
    - `Odoo Tutorials: Subscriptions <https://www.odoo.com/slides/subscription-20>`_
-   - :doc:`subscriptions/products`
-   - :doc:`subscriptions/plans`
-   - :doc:`subscriptions/upselling`
-   - :doc:`subscriptions/renewals`
-   - :doc:`subscriptions/closing`
-   - :doc:`subscriptions/automatic_alerts`
-   - :doc:`subscriptions/reports`
+   - :doc:`/applications/sales/subscriptions/products`
+   - :doc:`/applications/sales/subscriptions/ecommerce`
+   - :doc:`/applications/sales/subscriptions/plans`
+   - :doc:`/applications/sales/subscriptions/upselling`
+   - :doc:`/applications/sales/subscriptions/renewals`
+   - :doc:`/applications/sales/subscriptions/closing`
+   - :doc:`/applications/sales/subscriptions/automatic_alerts`
+   - :doc:`/applications/sales/subscriptions/reports`
 
 .. _subscriptions/quotations:
 
@@ -27,16 +30,17 @@ Subscription quotations
 .. important::
    Sales orders with a defined recurrence become subscriptions.
 
-To create a new subscription, click on :guilabel:`New` from the Subscription or the :doc:`Sales
-<sales>` app. You can either:
+To create a new subscription, click on :guilabel:`New` from the *Subscription* or the :doc:`Sales
+</applications/sales>` app. You can either:
 
-- Select a :doc:`subscription plan <subscriptions/plans>` to prefill the quotation instantly, or
+- Select a :doc:`subscription plan </applications/sales/subscriptions/plans>` to prefill the
+  quotation instantly, or
 - Fill out the quotation normally, making sure to select a recurrence and an end date if necessary
-  and adding :doc:`recurrent products <subscriptions/products>`.
+  and adding :doc:`recurrent products </applications/sales/subscriptions/products>`.
 
 .. tip::
    You can define different invoice and delivery addresses by enabling the :doc:`Customer Addresses
-   <sales/send_quotations/different_addresses>` feature.
+   </applications/sales/sales/send_quotations/different_addresses>` feature.
 
 .. _subscriptions/confirmation:
 
@@ -74,6 +78,7 @@ invoice manually.
    :titlesonly:
 
    subscriptions/products
+   subscriptions/ecommerce
    subscriptions/plans
    subscriptions/upselling
    subscriptions/renewals

content/applications/sales/subscriptions/ecommerce.rst

@@ -0,0 +1,52 @@
+=======================================
+Use subscriptions in the eCommerce shop
+=======================================
+
+Subscription products can be sold in the Odoo *eCommerce* shop just like regular sales products.
+
+However, by default, the eCommerce product page only displays the shortest recurrence period listed
+in the :guilabel:`Time-based pricing` tab of the product form. For example, if a subscription
+product has *monthly* and *yearly* recurrence periods configured, then only the monthly price
+appears on the eCommerce page for that product by default.
+
+To add more recurrence periods to the eCommerce product page, create a *product variant* for each
+recurrence period.
+
+.. seealso::
+   - :doc:`Configure subscription products </applications/sales/subscriptions/products>`
+   - :doc:`Product variants </applications/sales/sales/products_prices/products/variants>`
+
+Create recurrence periods as product variants
+=============================================
+
+To set up each recurrence period as a product variant, go to :menuselection:`Subscriptions -->
+Subscriptions --> Products` and select a product. In the :guilabel:`Attributes & Variants` tab,
+click :guilabel:`Add a line`.
+
+Create an :guilabel:`Attribute` called `Billing Period` (or something similar) by typing in the
+name and clicking :guilabel:`Create`. This attribute name appears as the option heading on the
+product page of the eCommerce shop.
+
+Next, create :guilabel:`Values` that correspond to the recurrence periods that are configured in
+the :guilabel:`Time-based pricing` tab of the product form. Type in the name of the recurrence
+period, then click :guilabel:`Create`. These value names appear as selectable options on the
+product page of the eCommerce shop.
+
+.. image:: ecommerce/recurrence-period-attributes-variants.png
+   :align: center
+   :alt: Recurrence periods configured as product variants in the "Attributes & Variants" tab of
+         the product form.
+
+Click on the :guilabel:`☁️ (cloud)` icon at the top of the page to save manually. After saving, a
+:guilabel:`Product Variants` column appears on the :guilabel:`Time-based pricing` tab. Assign the
+product variants to their corresponding recurrence periods and prices.
+
+.. image:: ecommerce/product-variants-time-based-pricing.png
+   :align: center
+   :alt: Product variants on the "Time-based pricing" tab of the product form.
+
+The product variants are now available for selection on the eCommerce product page.
+
+.. image:: ecommerce/recurrence-period-ecommerce.png
+   :align: center
+   :alt: Recurrence periods configured as product variants on the eCommerce product page.