This update was published over a year ago. Some of the information may be outdated.
It's now possible to export invoices created in Sliptree to Peppol BIS Billing v3.0 XML format, which is widely used in Europe for e-invoicing. This allows our users to send invoices to their customers via Peppol Access Points.
To export an invoice, simply open an invoice, click on More Actions and select Peppol BIS Billing v3.0 XML.

To export multiple invoices, go to the invoice list, select the date period that you want to export, click on Export and select Peppol BIS Billing v3.0 XML.

The exported file can be either emailed to your customer, or sent to your customer via a Peppol Access Point.
Some countries, like Latvia, provide a government portal for uploading and sending these files to your customers.