For most of your daily purchases, you already know where to buy them and what the prices are. For such purchases, a simple purchase order (PO) can help you handle the entire process.
In Odoo, a purchase order can be created this way, or it can be the result of a request for quotation or a purchase tender. However, every purchase has a purchase order.
The PO will generate an invoice. According to the contract between you and the supplier, you need to make payment before or after delivery.
Install Procurement Management Application
From Apps, search for and install the Procurement Management application.

Create Purchase Order
In the Purchasing module, open the Purchasing menu and click Purchase Order.

In the Purchase Order form, click Create.
From the new window, insert the supplier and enter the order date.

In the Product Details table, click Add.
Select a product from the list, and add a description if necessary.
Enter the quantity of the product you want to purchase, then click Save and Confirm Order.
Annotation
If you want to go through the complete process and create a purchase requisition for the order, please refer to the document :doc :
As you can see, the status of this purchase order has changed to "Purchase Order".

Register invoices, make payments, and receive products
According to the contract you signed with the supplier, you can pay upon delivery or receive payment after delivery.
Pay before or after receiving the goods
Still on the purchase order, click Receive Products.
On the next page, check whether the quantity of products received matches the order quantity, then manually enter the delivery quantity and click Confirm.

Return to the purchase order. In the purchase order, you will see two buttons: Receipt and Invoice.


Click the "Invoice" button, then click "Confirm". The invoice has been registered in the system. Click "Record Payment", enter the payment details, and then click "Confirm".
Your product is now displayed as ready for receipt and has been put into storage, and the invoice is also marked as paid.
Prepayment
On the Purchase Order page, open the Invoice tab, then click Create.
On the next page, click Verify. The invoice is registered in the system. Click Register Payment, insert payment details, then click Verify.

Return to the purchase order. In the purchase order, the Receipt Note and Invoice tabs are already displayed.

Click Receive Product, then click Confirm on the new page.

A window will appear asking if you want to complete everything at once. Click Apply.
Your product is now displayed as ready for receipt and has been put into storage, and the invoice is also marked as paid.
