[ADD] Sales: Created a new alternative products page

closes odoo/documentation#15681

X-original-commit: 16f062606d
Signed-off-by: Felicia Kuan (feku) <feku@odoo.com>
Signed-off-by: Thomas Jude Cavazos (thjud) <thjud@odoo.com>
Co-authored-by: Megan Valenzuela <meval@odoo.com>
Co-authored-by: Felicia Kuan <feku@odoo.com>

content/applications/sales/sales/products_prices.rst

@@ -12,3 +12,4 @@ Products & Prices
    products_prices/returns
    products_prices/ewallets_giftcards
    products_prices/loyalty_discount
+   products_prices/alternative_products

content/applications/sales/sales/products_prices/alternative_products.rst

@@ -0,0 +1,51 @@
+====================
+Alternative products
+====================
+
+The use of alternative products is a marketing strategy that involves upselling related products
+alongside a desired core product. For instance, by configuring alternative products, a customer
+could be suggested a mechanical keyboard or a wireless keyboard when they visit the eCommerce
+website page for a standard keyboard.
+
+.. note::
+   Alternative products are different from accessory and optional products because of where they
+   show up in the customer's shopping experience.
+
+   - Alternative products are suggested at the bottom of an eCommerce product page whenever the
+     product page is viewed. This creates an opportunity for upselling during the shopping process.
+   - Accessory products appear as suggestions when viewing an eCommerce cart. This creates an
+     opportunity for cross-selling during the checkout process.
+   - Optional products are suggested when a core product has been added to a cart or a quotation.
+     This creates an opportunity for cross-selling during the shopping process.
+
+Configuring alternative products
+================================
+
+To add an alternative product to a product form, navigate to :menuselection:`Sales --> Products -->
+Products` and choose a product. Ensure that the product's :guilabel:`Sales` checkbox is ticked and
+click the :guilabel:`Sales` tab. In the :guilabel:`Upsell & Cross-sell` section, click the
+:guilabel:`Alternative Products` drop-down menu to set alternative products. Products are displayed
+in alphabetical order. If the desired product isn't readily visible, type its name in the field to
+bring it up, then select it to add it as an alternative product.
+
+.. figure:: alternative_products/product-form-alternative-products.png
+   :alt: The alternative product field on the product form with multiple entries.
+
+   Entries in the :guilabel:`Alternative Products` field on a product form.
+
+How alternative products appear to customers
+============================================
+
+Although the **Sales** app is used to configure alternative products, customers will only encounter
+them when visiting a website created with the **eCommerce** app. Alternative products are
+automatically suggested during the shopping process when a customer visits the webpage for an
+associated core product. They appear underneath the product listing under the header
+:guilabel:`Alternative Products`.
+
+.. figure:: alternative_products/alternative-products-ecommerce.png
+   :alt: Alternative products as they appear on an eCommerce website.
+
+   The alternative products section of an eCommerce product page.
+
+.. seealso::
+   :doc:`/applications/websites/ecommerce/products/cross_upselling`