An operación exenta is a transaction that falls within Spanish VAT but where, by law, no VAT is charged on the invoice: this covers healthcare, education or residential rentals, among other activities listed in article 20 of the VAT law. The exemption depends on the activity, not on your turnover, and it is different both from a non-subject transaction and from a low-income VAT franchise, which does not exist in Spain.
The expensive nuance: most of these exemptions are "limited", meaning you charge no VAT but you also cannot deduct the input VAT linked to that activity, and if you mix exempt and non-exempt activities the pro rata rule kicks in. If someone told you that you can invoice without VAT because you earn little, read our guide on the 85,000 euro myth.
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