If you want to request an invoice, you can do so in two ways:
1. Through the invoice portal (Requires registration with a Government Issued ID) by going to www.portalcliente.mercadona.es
Once you have registered on the portal, from "Online Invoice" you can:
• Register billing information to receive invoices for your orders.
• Modify invoicing frequency (monthly / per order).
• View, download and print your invoices.
• Request invoices for your physical in-store purchase receipts.
2. By calling the toll-free Mercadona customer support number 900 500 103 and choosing Option 4