There are a couple of different ways to create a credit note / credit invoice. Both will add a credit to a customer account.
1) Create a credit note
Navigate to invoices>draft credit note and selecting the NEW button.
Select location and then the account you wish to credit.
You can then add the products that you want to credit and set the dates that the credit applies to.
You can also select the reason for the credit note and the type of credit (system or human error).
Once saved, this credit note will be in draft format just like an invoice - and will need to be approved to credit the account.
Once approved, the credit will show up on the customer Accounts Receivable detail and credit the total balance of the account by the credit note amount.
2) Create a credit note from a specific invoice
If you need to credit back an invoice that has multiple line item charges, rather than have to enter in each line item on a new draft credit note, you can credit a specific invoice which will generate credits for all charges on the invoice. Follow the steps below:
Click on the invoice number you wish to credit. To do this navigate to invoices list view and click into the blue invoice number of the relevant invoice. In this example we are crediting invoice FNY-23
Once you have clicked into the invoice detail page, you will see a credit invoice button on the right. Click this button.
A draft invoice is generated with all of the line items from the original invoice that you are crediting, as well as reference that the credit is for invoice FNY-23
You can choose to delete items from the draft credit note that you don't wish to credit, or add new items on. Once complete you would save as a draft credit invoice and then approve to apply the credit to the account.