View Source

On this tab, you can specify how you want to use this debit note:

To apply as a payment against the invoice received, which was used as the basis, or to other invoices received
To post as an advance payment that can be used as a basis for refund or can be applied to other invoices received.

FirstBit User Guide > 4.2.6.2.4. Creating a Debit Note. The Settlements tab > image2018-12-18_16-35-11.png
The "Credit Note (create)" form. The Settlements tab

Unless you specify otherwise, the system by default will automatically apply the debit note as a payment to the invoice received used as the basis. If the debit note amount is greater than the invoice balance, then the excess amount will be used as an advance.

Thus, if you want to apply the debit note against the original invoice received, you can leave this tab as it is. If you want to use the debit note as an advance payment, click Fill by Balances, and then select the Advance check box for each line.