[IMP] update content of "Down Payment" (Sales V13 - CDU) (#577)

sales/invoicing/down_payment.rst

@@ -2,44 +2,98 @@
 Request a down payment
 ======================
 
-A down payment is an initial, partial payment, with the agreement that
-the rest will be paid later. For expensive orders or projects, it is a
-way to protect yourself and make sure your customer is serious.
+A down payment is a partial payment made by the buyer when a sales contract is concluded. This
+implies both parties' full commitment (seller and buyer) to honor the contract. With a down payment,
+the buyers show their will to acquire the product and agree to pay the rest later, while the sellers
+are obliged to provide the goods by accepting it.
+
+Sometimes a down payment is required for expensive orders or projects. That way, you can protect
+yourself and make sure that your customer is reliable.
 
 First time you request a down payment
 =====================================
 
-When you confirm a sale, you can create an invoice and select a down
-payment option. It can either be a fixed amount or a percentage of the
-total amount.
+When a sales order is confirmed, you then have the possibility to create an invoice. Invoices
+are automatically created in drafts so that you can review them before validation. To create an
+invoice, Odoo Sales offers you 3 options:
 
-The first time you request a down payment you can select an income
-account and a tax setting that will be reused for next down payments.
+- Regular invoice
+- Down payment (percentage)
+- Down payment (fixed amount)
 
-.. image:: media/down_payment01.png
+In terms of down payment, it can either be a fixed amount or a percentage of the total amount. The
+first time you request a down payment, you can set a percentage or a fixed amount of your choice,
+and select the right income account and taxes. These settings will be reused for future down
+payments.
+
+.. image:: media/down_payment_1.png
    :align: center
+   :alt: How can you do a down payment on Odoo Sales?
 
-You will then see the invoice for the down payment.
+.. important::
+   When you request your first down payment, a new product called **Down payment** will be created.
+   This product will be registered as a **service** product with an invoicing policy of
+   **ordered quantities**. As a reminder, you can edit this product and modify it at any time.
+   Please note that if you choose **delivered quantities** as invoicing policy,
+   **you will not be able to create an invoice**.
 
-.. image:: media/down_payment02.png
+Basic sales flow using down payments
+====================================
+
+For this first example, we will use a 50% amount down payment with a product using
+**ordered quantities** as invoicing policy. Make sure to check out our documentation about invoicing
+policies here: :doc:`invoicing_policy` , before requesting your first down payment. When it comes to
+create and view the invoice, you will only have access to a draft invoice mentioning the down
+payment (as you can see below).
+
+.. image:: media/down_payment_2.png
    :align: center
+   :alt: What is a basic sales flow using down payments on Odoo Sales (1)?
 
-On the subsequent or final invoice, any prepayment made will be
-automatically deducted.
+There, you can post the invoice and register the payment of your customer. But, we all know that in
+real life this flow does not happen immediately. So, for now, you can return to the sales order.
+There, you will have the possibility to see the order as a customer with the **Customer preview**
+button or to reach easily the previous draft invoice with the **Invoice** button. In any case, the
+down payment will be mentioned on both (sales order and draft invoice).
 
-.. image:: media/down_payment03.png
+.. image:: media/down_payment_3.png
    :align: center
+   :alt: What is a basic sales flow using down payments on Odoo Sales (2)?
+
+To complete the flow, when the customer wants to pay the rest of his sales order, you must create
+another invoice. Once again, you will have the choice to make another down payment or to deduct all
+the down payments and so, paying the rest of the invoice as a regular invoice.
+
+.. image:: media/down_payment_4.png
+   :align: center
+   :alt: What is a basic sales flow using down payments on Odoo Sales (3)?
+
+This flow is also possible with a down payment taking into account a fixed amount.
+
+.. important::
+   Be careful that if you do a down payment with a product using **delivered quantities** as
+   invoicing policy, you won’t be able to deduct all the down payments when it comes to invoicing
+   your customer. Indeed, you have to deliver a product before creating the final invoice. If
+   nothing has been delivered, you create a **credit note** that cancels the draft invoice
+   created after the down payment. To do so, you have to install the **Inventory App** to confirm
+   the delivery. Otherwise, you can enter the delivered quantity manually on the sales order.
 
 Modify the income account and customer taxes
 ============================================
 
-From the products list, search for *Down Payment*.
+From the products list, search for the **Down Payment** product.
 
-.. image:: media/down_payment04.png
+.. image:: media/down_payment_5.png
    :align: center
+   :alt: Creation of a down payment product on Odoo Sales
 
-You can then edit it, under the invoicing tab you will be able to change
-the income account & customer taxes.
+You can edit it and under the **General Information Tab** you will be able to change the customer
+taxes. Now, to change the income account, you will need to install the **Accounting App** to have
+the possibility to see the **Accounting Tab** on the product form.
 
-.. image:: media/down_payment05.png
+.. image:: media/down_payment_6.png
    :align: center
+   :alt: How to modify the income account link to down payments
+
+.. seealso::
+  - :doc:`invoicing_policy`