a. If you are using practitioner commissions and Approving your Pending Commissions for Payment you will ALWAYS do a refund do not VOID invoices unless you are voiding the item straight away before approving it in the Pending Commissions.
b. Refunds for products will add the item back into Inventory if you are using the Track Inventory feature.
1) Navigate to Home>Billing tab>Quick Invoice.
2) In the Qty field, add a negative - before the quantity of the item being returned.