You can add a new Credit directly from the Credits Screen. To do this, click the Add Credit button in the upper right corner of the screen:
This will open the Add Credit overlay:
Select an Account from the dropdown list. If the Account has any open Invoices, these will populate when you select an Account. The Date of Credit will default to the current date. Change this if needed. The Reference Number field is required. Even if you are not using any particular reference number for this transaction, you will not be able to save the Credit without entering something in this field.
If the Credit actually represents an amount that was refunded to the client in a transaction outside of SA (such as writing the client a check), switch the toggle on Is Refunded. This will reveal additional options that are necessary for a Credit Refund:
To add an amount to the Credit, regardless of whether or not it's a refund, you will need to add a Line Item and Rate. As you add Line Items, the totals will update at the bottom of the overlay. Check boxes next to Invoices to apply the Credit:
Be careful how you apply the Credit. Once the Credit is saved, you will not be able to change the allocation. If the allocation needs to be changed you will need to delete the Credit and create a new one.
Add a Memo if you have any additional internal notes about the Credit. Be sure to click Save Credit when you are finished.