NAV Online Számla
NAV Online Számla is the Hungarian tax authority's system to which invoicing software reports the data of domestic invoices.
Updated:

What does NAV Online Számla mean?
Since 1 January 2021, as a rule, the data of every invoice issued in Hungary must be reported, including invoices to private individuals; in that case the buyer's personal data is not reported. The invoicing software does the reporting when the invoice is issued.
Exceptions, deadlines and penalties are set out on the NAV Online Számla site and in the VAT Act; check the details for your case with your accountant.
Why does it matter to a small business?
For a small business, what matters most about NAV Online Számla is that its invoicing software reports properly, and that there are no forgotten invoices issued by hand outside the system. When every invoice goes out from one place, through one connected invoicing account, gaps and double issuing are less likely. Check the details on NAV's site and with your accountant.
What does it look like in practice?
Details
Suppose an electrician in Szombathely makes his invoices in HelloCRM and has connected his own Számlázz.hu account. When he issues an invoice after a job, Számlázz.hu issues it and reports it to NAV, and the PDF is kept in HelloCRM too. If he made a mistake, he does not edit the issued invoice but reverses (storno) or corrects it.
How does HelloCRM handle it?
Details
HelloCRM does not report to NAV itself: Számlázz.hu or Billingo issues the invoice from your own account and does the reporting. Proformas are never reported, and the same invoice cannot be issued twice.
Module: Invoicing (paid module, price coming soon).
A CRM for small businesses in Hungary
HelloCRM is an online CRM made in Hungary for small and mid-sized businesses there, in Hungarian and English: the core CRM is free for good, with no time limit and no card, and it can be tried without signing up in a demo company full of example data.
Questions
What is NAV Online Számla, in one sentence?
NAV Online Számla is the Hungarian tax authority's system to which invoicing software reports the data of domestic invoices.
Sources
This is general information, not legal or tax advice. The rules come from: NAV Online Számla (checked ); 2007. évi CXXVII. törvény az általános forgalmi adóról (Áfa tv.), Nemzeti Jogszabálytár (checked )