Types of Invoices: What They’re For and What They Should Include
You’ve probably heard there are different types of invoices, but it’s normal to get confused about what each one is for and what details they should include.
If that’s the case, don’t worry — this article clears it all up.
Table of Contents
- Standard Invoice
- Corrective Invoice
- Summary Invoice
- Proforma Invoice
- Simplified Invoice
- Electronic Invoice
Standard Invoice
As the name suggests, the standard invoice is the most common type — it’s the one you’ll create regularly whenever you sell a product or service.
We won’t go into detail here about how to create one or what to include, since you can find everything you need to know in [this article].
Corrective Invoice
Also self-explanatory, a corrective invoice is used when you need to fix or update information from a previously issued invoice due to errors. For example:
- Products are returned after the invoice was issued
- A discount is applied after invoicing
- The client information or invoice details are incorrect
- Taxes (VAT or income tax) were applied incorrectly
- A key detail like the due date was left out
When should you issue a corrective invoice?
As soon as you’re aware of the mistake — though legally, you can correct it up to 4 years from the date of the original invoice.
You can also issue a single corrective invoice that amends several invoices, as long as each one is clearly referenced.
What must a corrective invoice include?
In addition to the usual invoice data, it should also contain:
- Reference to the original invoice(s), including number and issue date
- The nature of the correction (e.g., -€100 if a product is returned)
- A clear indication that it’s a corrective invoice
- The reason for the correction
- Taxes (VAT and income tax) as required on standard invoices
Summary Invoice
A summary invoice lets you group multiple transactions made on different dates into one invoice, as long as they were all for the same customer and occurred within the same month.
It’s a time-saver: instead of issuing an invoice for every transaction, you send just one for the whole period.
Note: You can’t use a summary invoice to group transactions over more than one month.
Proforma Invoice
A proforma invoice is a temporary invoice issued to give your client details about a potential future purchase.
It should include:
- The taxable base
- Applicable taxes
- Total price
- (Recommended) Validity date
- A clear note stating that it is a proforma invoice
Proforma invoices are informative only — they don’t have legal or accounting value, and you don’t need to number them. However, they may serve as supporting documentation if there’s a payment dispute.
Key differences from a standard invoice:
- A proforma invoice is like a draft; a standard invoice is final
- Proformas are issued before delivery and don’t require payment; standard invoices confirm the sale and do require payment
Simplified Invoice
The simplified invoice is what we’ve traditionally called a receipt or sales ticket.
If you run an e-commerce business and provide customers with a proof of purchase, that’s typically considered a simplified invoice.
It must include:
- Each product or item sold
- The price per item, including VAT
Limits:
- Max total: €400 including VAT
- For some sectors (retail, transport, hairdressing, etc.): up to €3,000
Differences from a standard invoice:
- Simplified: includes only issuer data; Standard: includes issuer + customer
- Simplified: VAT only; Standard: VAT + income tax
- Simplified: total amount shown; Standard: itemized breakdown
- Simplified: products/services named; Standard: detailed descriptions
If a simplified invoice exceeds €400 (VAT included), a standard invoice must be issued.
Electronic Invoice
Today, most businesses have moved away from paper invoices — especially if you run (or plan to run) an online business, your invoices will likely be 100% digital.
Since 2013, electronic invoices are legally valid and must include the same information as standard paper invoices.
Electronic signatures used to be mandatory, but since 2013 they’re optional (though still recommended).
Yes, every type of invoice comes with its own requirements and quirks — and yes, it can be a headache to keep them all straight without making a mistake.
But it doesn’t have to be that way.
With Companio One Spain, you can create invoices in minutes and stop worrying about billing and tax declarations. And if you’re a first-time freelancer, registration is completely free.
