How to do electronic invoicing in Mexico (2026 guide)

What you need before issuing your first invoice

To invoice in Mexico you need exactly four things, all free before the SAT: your active RFC with an obligation to invoice, your current e-signature (previously FIEL), a Digital Seal Certificate (CSD) and a billing system connected to an authorized PAC.

The most common mistake is to confuse e.firma with CSD. The e.signature identifies you as a person before the SAT (it is used for procedures); The CSD is the certificate with which you "sign" each invoice. The CSD is generated with your e-signature from the SAT portal in about 10 minutes and takes up to 72 hours to activate.

• Active RFC with a regime that allows billing (RESICO, Business Activity, Legal Person, etc.).
• e.valid signature - is processed by appointment at the SAT, lasts 4 years.
• CSD generated with the SAT Certifica app and uploaded to your billing system.
• A PAC (Authorized Certification Provider) that rings: you almost never hire them directly, they are included in your billing software.

The step-by-step billing process

Once the CSD is configured, issuing a CFDI 4.0 always follows the same flow. With a good system, steps 2 to 5 happen on their own in seconds.

• 1. You capture the client's data: RFC, EXACT company name as it appears in their Tax Status Certificate, zip code and tax regime. In CFDI 4.0, any discrepancy rejects the stamping.
• 2. You add the concepts with their product/service key from the SAT catalog and the unit key.
• 3. You define use of the CFDI (G01 acquisition, G03 expenses, P01 to be defined no longer exists in 4.0), payment method (PUE an exhibition / PPD partialities) and payment method.
• 4. The system seals the invoice with your CSD and sends it to the PAC, which stamps it and registers it with the SAT.
• 5. You deliver to the client the XML (the actual tax document) and the PDF (the printed representation).

The errors that will make you reject invoices

CFDI 4.0 validates against SAT databases in real time, so errors are detected when ringing, not afterward. These are the ones that reject the most invoices in 2026:

• Company name with minimal differences: "S.A. DE C.V." written when the record does not include it. In 4.0 the company name goes WITHOUT the corporate regime.
• Recipient's postal code that does not match their registered tax address.
• Tax regime of the recipient incompatible with the use of CFDI chosen.
• Billing with an expired or revoked CSD — review the validity each year.
• Issue PUE (payment at a show) when the client will pay later: PPD + payment supplement when collecting corresponds.

Billing connected to your operation: the real savings

Invoicing "by hand" in the SAT portal is free but does not scale: you capture everything twice (once in your sales control, another on the invoice) and there is no inventory, collection or reports connected.

The real difference is in invoicing from the same system where you sell. In Aura, each sale from the point of sale, the online store or a CRM order can be converted into CFDI with one click: the customer data is already captured, the stamping is automatic and the invoice lowers inventory and feeds your accounting at the same time.

In addition, self-invoicing allows your client to generate their CFDI alone, from a link, with their purchase receipt — zero time for your team on "can you invoice me for this ticket."

How much does it cost to invoice in 2026

The cost per ring in Mexico ranges from $0.50 to $2 MXN depending on the provider and volume, plus the monthly software fee. "Loose" billing systems cost $200-600 MXN/month, but they only invoice: no inventory, no collections, no sales.

If you already need to operate the entire business, a system where billing is another module is convenient. Aura includes CFDI 4.0 billing with stamping, payment add-ons, cancellations and self-invoicing within the Aura One plan, along with POS, inventory, CRM and WhatsApp. You can try it for 14 days for $14 USD.