A Simplified Invoice differs from a regular invoice in that it is an auto-paid sales document; that is, as soon as the document is issued, it is automatically considered paid. However, for a regular invoice, a separate receipt must be issued for it to be considered paid.
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A Simplified Invoice has a value limit depending on the type of activity. For retailers and street vendors, the issuance of Simplified Invoices is allowed for non-taxable persons, as long as the amount does not exceed €1,000. For other activities, a Simplified Invoice can be issued as long as the amount does not exceed €100. If these limits are exceeded, a Receipt Invoice must be issued instead of a Simplified Invoice.