Is electronic invoicing (FEL) mandatory in Guatemala and what is needed to issue it?

Yes. The FEL regime (Online Electronic Invoicing) was created by SAT Board Agreement 13-2018, in force since May 23, 2018, and modified by Board Agreement 26-2019; it covers the issue, transmission,… certification and retention of electronic tax documents (DTE: invoices, credit and debit notes, receipts). Adoption was progressive: VAT taxpayers required from July 2022, small taxpayers from 31 March 2023, and from mid-2023 the pre-printed invoice ceased to be valid - the obligation is now universal. Every issuer needs an authorized certifier (or SAT's free app) and an electronic signature; invoicing reaches SAT in real time, which matters for due diligence on counterparties.