[IMP] accounting: update doc about Purchase Receipts

+ rename bills_or_receipts.rst -> purchase_receipts.rst

accounting/payables/supplier_bills/purchase_receipts.rst

@@ -0,0 +1,45 @@
+=================
+Purchase Receipts
+=================
+
+**Purchase Receipts** are not invoices but rather confirmations of received payments, such as a
+ticket or a receipt.
+
+This feature is meant to be used when you pay directly with your company's money for an expense.
+**Vendor Bills**, on the other hand, are recorded when an invoice is issued to you and that the
+amount is first credited on a debt account before a later payment reconciliation.
+
+.. note::
+   Expenses paid by employees can be managed with **Odoo Expenses**, an app dedicated to the
+   approval of such expenses and the payments management. Click :doc:`here
+   <../../../expense/expense>` for more information on how to use Odoo Expenses.
+
+Register a receipt
+==================
+
+To record a new receipt, go to :menuselection:`Accounting --> Vendors --> Receipts`, click on
+*Create*, fill out the form, and click on *Post*.
+
+.. image:: media/purchase_receipts_draft.png
+   :align: center
+   :alt: Fill out the draft purchase receipt in Odoo Accounting
+
+You can register the payment by clicking on *Register Payment*, then filling out the payment's
+details, and clicking on *Validate*.
+
+Edit the Journal Entry before posting it
+========================================
+
+Once you have filled out the *Invoice Lines* tab, you can modify the **Journal Entry** before you
+post it.
+
+To do so, click on the **Journal Items** tab, change the accounts and values according to your
+needs, and click on *Post*.
+
+.. image:: media/purchase_receipts_journal_items.png
+   :align: center
+   :alt: Change the accounts used in the journal entry to record a purchase receipt.
+
+.. seealso::
+   - :doc:`manage`
+   - :doc:`../../../expense/expense`