A credit invoice is a document that lowers the amount you need to pay on one of your invoices. You may also know it as a credit note. Both names mean the same thing.
Credit invoices make sure you only pay for what you actually use.
When a credit invoice is issued, the amount is subtracted from your invoice automatically, so you do not need to request a refund or calculate anything yourself.
Where to view them
To see all your credit invoices:
Go to 
Billing & Assets -> Invoices and open the "Credit invoices" tab at the top.
What you can see
The Credit invoices tab gives you a clear overview of every credit you received.
For each one, you can see:
Status: Whether the credit was applied.
Invoice No.: The credit invoice number.
Created at: The date it was created.
Applied to invoice: The invoice the credit was subtracted from.
Amount: The credit amount.
Total: The total credit amount.
Paid: The amount already applied.
View: Open or download the PDF copy.
✅ Credit amounts are shown with a minus sign (for example, -2.42 EUR), because they reduce what you pay.
How credit invoices work
Each credit invoice is linked to one of your regular invoices. The credit amount is subtracted from that invoice, and you only pay the remaining amount.
For example, if your invoice is 100 EUR and a credit invoice of 20 EUR is applied to it, you pay 80 EUR for that invoice instead of 100 EUR.
This also works with automatic payments. If you pay with a bank card, your card is charged only the reduced amount.