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In Odoo 9, payments are generally registered against vendor bills rather than purchase receipts. However, if you need to register a payment at the purchase receipt stage, here are your possible solutions:

Solution 1: Register Payment via Vendor Bill (Standard Approach)

Odoo's accounting system expects payments to be linked to vendor bills, so the recommended process is:

1. Create a Vendor Bill
   • Go to Purchases > Vendor Bills.
   • Click Create and select the supplier.
   • Ensure that the bill includes the items received.
2. Validate the Vendor Bill
   • Click Validate to confirm the bill.
   • This will generate an accounts payable entry.
3. Register the Payment
   • Click Register Payment on the vendor bill.
   • Choose the payment method (bank, cash, etc.).
   • Confirm the payment.

Solution 2: Record an Advance Payment (Prepayment)

If you want to register a payment before receiving the vendor bill, you can create a prepayment:

1. Create a Manual Payment
   • Go to Accounting > Payments > Create.
   • Select Vendor as the partner type.
   • Enter the supplier’s name and the amount paid.
   • Choose the payment method and confirm.
2. Reconcile Payment with Vendor Bill
   • Once the vendor bill is created, go to Accounting > Reconciliation.
   • Select the prepayment and the vendor bill.
   • Validate the reconciliation to match them.

Solution 3: Customization for Direct Payment at Purchase Receipt

Odoo 9 does not have a built-in way to register payments directly at the purchase receipt stage. If you need this functionality, you may have to customize Odoo to:

• Allow payments to be linked to purchase receipts.
• Automatically create vendor bills at the time of receipt.

For customization, you can:

• Develop a custom module.
• Use Odoo's payment terms and journal entries to track payments against received goods.

Conclusion

Odoo’s default flow requires vendor bills for payment registration. If your process requires direct payments at purchase receipt, you might need to handle it through prepayments or customization.