Creating an proforma invoice
Start by clicking on Client in the left panel. Then click on the Sheets icon
2. Switch to the proforma Invoices tab and use the CREATE NEW PROFORMA INVOICE button
3. For the sake of clarity, it is then appropriate to mark the proforma invoice as paid when payment is received from the customer
This will also turn the Payment Invitation into a Tax Document in the Export column. However, by clicking on the arrow you can download both documents at any time; regardless of the payment status.
When you subsequently create a new invoice or a new quick invoice, you are notified in both the first and second steps that backups have been invoiced:
...and in the third step you have the option to subtract them: