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Issuing certified electronic invoice

There is a possibility to issue certified electronic invoice in CO3. These invoices not require printing, are transmitted electronically and stored electronically. Certified electronic invoices are signed with CO3 Kft.'s own enhanced security certificate, and receive a time stamp from a qualified service provider. The certificate is a certified certificate used for electronic signatrure and encryption. A timestamp proves the existence of any electronically stored information at a moment. The electronic signature and time stamp of the invoices can be used for a separate unit price fee. The unit price of the timestamp varies per subscription plan.

You can see your current timestamp balance at the top of the Finance tab:


You can choose to top up your balance by clicking 'Top up.':


Here you can set how much you want to top up your balance. The system allows payment by card and bank transfer also. You can provide an electronic signature and timestamp to your invoice by selecting one of the electronic methods at the bottom of the invoice when recording:

  • Print invoice to PDF or
  • Send e-invoce to customer If one of the above options is selected, "E-signature and timestamp" will be active.


By selecting this, the invoice will be prepared by including CO3 Kft.'s own enhanced security certificate and the time stamp from the qualified service provider.After the invoice is issued, the time stamp balance is reduced by the unit price of the time stamp.

Invoices with an electronic signature and time stamp are automatically stored after they are issued or emailed.

Reprinting a valid e-invoice

The reprint of an e-invoice is no longer the same invoice as the one originally issued and sent to the customer, as it was not downloaded again at the same time. Therefore, when it is reprinted/downloaded, it is no longer an e-invoice, but only the term Invoice is printed on the invoice, indicating that it is no longer the original invoice with the time stamp.

The PDF version of the e-invoice is automatically saved and attached to the invoice as soon as it is issued. This ensures the legal obligation to keep the invoice for 5 years. The attached PDF can be accessed in two ways:

  • In the invoice list, at the beginning of the invoice line, there is a small paper icon in grey. When you hover the mouse over it, the text "View invoice image" appears. Clicking on this will immediately download a PDF containing the original certified e-invoice.
  • You can also access these invoices from the Invoice Images folder in the Documents module. The invoice names start with the prefix invoice followed by the invoice serial number, where the / sign is replaced by. So, for example, invoice 00202/2023 will be named: invoice_00202_2023.pdf . Clicking on the document will download the invoice in PDF format, which also contains the original authentic e-invoice issued.

In both cases, the same file will be downloaded, it is up to the user to decide which access is more convenient for him/her.

Can I send an e-invoice to multiple recipients? Yes, you can. Enter email addresses separatedly in the email address field by commas, when finalizing your invoice.

Certified electronic invoicing has a legal background. Please contact with your accountant to know more about it.

Please note that this section is valid mainly for Hungarian users.