Manage Credit Memo
Once the invoice is generated and the shipment is done, both the Invoice button and the Ship button disappear from the top navigation bar. The Credit Memo button appears as soon as the invoice is generated and remains on the Order View page until the Admin has released the net earned amount to the vendor. This button is used to create the refund on customer request.
Go to Vendor panel > Manage Order > Manage Credit Memo to check credit memo list.