Invoice mistakes happen. A customer changes a billing address, a line item has the wrong amount, or a discount was missed. The important part is how clearly you correct it.
Find the mistake#
Open the invoice and identify what changed: customer details, line items, tax, total, due date, or payment status. Small mistakes and money mistakes should not be handled the same way.
Edit if the invoice is still in review#
If the invoice has not been paid and the customer has not processed it, editing and resending may be enough. Add a short note so the customer knows what changed.
Use a credit memo for money adjustments#
If the customer paid too much, received a refund, or needs a documented credit, create a credit memo. This keeps the adjustment visible instead of quietly changing history.
Tell the customer clearly#
Do not send a corrected invoice with no explanation. Tell the customer what changed and what they should use going forward.
A simple decision rule#
If the invoice is wrong before payment, edit and resend. If money needs to be credited back or documented separately, use a credit memo.