When entering a credit note, it is possible to view which portion of the total credit note amount is to be applied as a taxable amount and which as a non-taxable amount.
To find out this breakdown, access the calculation utility by clicking on the "Distribute taxable and non-taxable amounts" icon to the right of the "Credit note amount" field. (The icon becomes visible when you move your mouse over it).
Once the result is displayed, click on the green tick to confirm the amount of the credit note.
The "See details" icon in the window opens all the lines making up the invoice. This makes it easy for the user to manually modify the fields targeted for the current credit note.
Note that, by default, the taxable amount of a credit note takes into account the taxes of the invoice on which it is distributed, even if the taxes applicable to the matter and/or the client have been modified since the invoice was produced.
It is important to note that the utility does not influence the automatic distribution of the credit note. Users wishing to assign specific lines must do so manually.