Corrective invoices: when they are needed, when they are not and common mistakes

“Does this need a corrective invoice?” is one of the questions most often asked by the admin team of an online store. And the answer is not always yes. Some changes require one, others do not, and some errors are fixed in a way that creates a bigger problem than the original.

We will not talk here about how to number invoices, which is another topic. We will look at when a corrective invoice is needed (in Spain, a factura rectificativa: the document that legally amends an invoice already issued), what it must contain and the mistakes that keep recurring in PrestaShop stores.

The underlying rule: an issued invoice is not touched

An issued invoice is neither deleted nor edited. If it contains an error or if the transaction changes afterwards, it is corrected with another document: the corrective invoice. That rule, which already existed, carries even more weight with invoicing systems that record each invoice in a way that cannot be altered without leaving a trace, as required by the Verifactu regulation (Real Decreto 1007/2023, the Royal Decree that sets the requirements for invoicing software in Spain).

In practice, “touching up the PDF” or changing amounts in the database for an invoice already delivered to the customer or to the accounts is not a correction: it means having two versions of the same invoice.

When a corrective invoice is needed

When the invoice contains an error

• Wrong amounts, VAT rate or VAT calculation.
• Incorrect or incomplete recipient details where they are mandatory, for example a misspelt NIF (Spanish tax ID) on a full invoice.
• A line that does not belong or one that is missing.

When the transaction changes after invoicing

• Returns of products, full or partial.
• Discounts granted after the sale, such as a credit for a product that arrived damaged.
• Orders cancelled after being invoiced.
• Rebates or volume discounts calculated at the end of a period in sales to businesses.

When it is not needed

• The order has not been invoiced yet. If you cancel or modify an order before the invoice is issued, there is nothing to correct. That is why it matters at which order status PrestaShop generates the invoice: generating it when the order is created, rather than when it is paid, multiplies corrective invoices.
• A change of size or colour at the same price. If the customer swaps a product for another of the same amount and the same VAT rate and no money is refunded, the invoiced transaction does not change. Record the exchange in the order, but you do not always need a correction. If the amount changes, you do.
• Errors in documents that are not invoices, such as the delivery note or the order sheet.
• A customer who wants their invoice with a different design. The format is not an error.

The case of a customer who asks for a full invoice with their NIF after having received a simplified one (factura simplificada, the Spanish receipt-style invoice that does not include the buyer's full details) has its own rules; check it with your accountant.

What a corrective invoice must include

In addition to the details of any invoice, a corrective invoice must:

• State that it is a corrective invoice.
• Identify the invoice it corrects: number and date.
• Explain the reason for the correction.
• Show the correction: the tax bases, rates and amounts being corrected, or the new amounts.
• Belong to a specific series, separate from ordinary invoices.

And it is issued when the reason for the correction becomes known, not weeks later “to do them all together”.

Common mistakes in PrestaShop

1. Editing the original invoice in the database to change an amount. The customer has one version, the accounts another.
2. Credit slips generated with amounts that do not match what was actually refunded, because someone ticked the wrong refund option or typed in an amount by hand.
3. Credit slips with zero lines that break the PDF template when opened.
4. Shipping handled differently in the actual refund and in the document.
5. Corrective invoices in the same series as normal invoices, or series mixed up when the store invoices in territories with different taxes (mainland Spain, the Canary Islands, Ceuta and Melilla).
6. Corrective invoices that never reach the accounts because the ERP only imports invoices and nobody configured credit slips.
7. An outdated store that carries tax calculation and rounding errors already fixed in later versions of PrestaShop.

An example: partial return with shipping

A customer buys three units of a product and also pays for shipping. They return one unit because they do not need it. The correct approach is a corrective invoice that identifies the original invoice, explains that it is a partial return and shows the tax base and VAT amount for that unit, at the price actually paid (with any order discount prorated). Shipping is not included unless your terms say otherwise, because the original delivery was provided in full.

The wrong approach, and the one we see often, is any of these three: cancelling the whole invoice and issuing another for two units, editing the original invoice, or making the refund on the gateway and forgetting about the document.

Correcting a credit slip before it is final

There is a practical nuance. PrestaShop generates the credit slip automatically when a partial return or refund is recorded, and does not let you change it afterwards. If that credit slip came out wrong (a quantity, an amount, the shipping) and has not yet left the store (it has not been sent to the customer, to the accountant or to an invoicing system that records it), the sensible thing is to correct it and regenerate the PDF. If it has already been recorded elsewhere, the correction is another document.

How to handle it in PrestaShop

The corrective invoice editor lets you modify PrestaShop credit slips from the back office, without touching the database by hand: quantities, prices and amounts for each line with and without VAT, adding or removing order lines, discounts and surcharges, shipping costs, date and an internal note. It recalculates each line according to its VAT rate, has buttons to recalculate totals and reset from the order, and when saving it removes the zero lines that break some PDF templates. It installs no overrides and is compatible with PrestaShop 8 and 9. To organise numbering, the multiple invoice series module assigns each invoice a series with its own prefix according to country or province, or customer group, with optional annual reset, numbering of invoices already issued and CSV export for your accountant; you define the tax regime of each series.