To change the deadline for one invoice:

1. Open the invoice in edit mode
2. In the Invoice Details card, update the "Due date" field
3. Save the invoice

If you want future invoices to start with a different deadline, update the customer's payment terms or the default at Settings → "Facturen en offertes" under "Hoeveel dagen krijgt een klant om te betalen?" (how many days does a customer get to pay?).

Tip: Automatic payment reminders follow the due date, so a correct deadline also means reminders go out at the right moment.

If a customer has no payment terms of their own, the workspace default at Settings → Facturen en offertes is used before falling back to the platform default (14 days). That order used to be skipped when selecting a customer, which could produce an earlier due date than intended.

Generated invoices from contracts and recurring invoices also receive a due date. They use the contract's or recurring invoice's own payment-term field when one is set; otherwise they fall back to the platform default, just like manually created invoices.