Void an invoice – Help Centre

In Heyquip: Billing > Invoices

You will have the invoice marked voided, its value taken back off the books today, and the order's value back on the to-bill pile.

Steps

Go to Billing > Invoices and open the invoice.
Click Actions, then Void invoice.
In the Reason box, type why you are voiding the invoice. The box asks "Why is this invoice being voided?"
Click Void invoice to confirm, or Cancel to back out.

When you finish, the invoice is still there and still readable, marked as voided, and the order can be invoiced again.

The invoice is not rewritten. It stays exactly as it was billed, so every report you have already run keeps its figures.
No credit note is created. Voiding is not a credit. Nothing goes to the customer's account, except if they had already paid their invoice.
The books take the value off today, in the current period, rather than reaching back to the invoice's own date. That is what keeps a closed period intact.
The printed invoice says so. Its PDF is marked voided across the page.
The order goes back on the to-bill pile. What the order is worth becomes billable again, and you can raise a corrected invoice.

Voiding and crediting are two different operations.

Void invoice: the invoice stays on file, marked. Use it when the invoice is wrong but the order is not: void the invoice, then invoice the order again.
Credit: the customer keeps the invoice and gets money back against it. Use it when the bill was right at the time and something changed after. See Credit an order in full.

Both the order action and the invoice action are called "Annuler" in French: Annuler la commande and Annuler la facture. They are two different operations.