Go to System → Settings → Checkout
Invoices numbers generated manually by the store owner (administrator) on the order page. Do not confuse Order ID with Invoice ID (number). The difference between a sales order and a sales invoice is that a sales order is initiated by a customer who is electing to purchase something from the business and a sales invoice is the document a company uses to bill the customer for that purchase. A sales invoice isn’t initiated until a sales order has been processed. |
Set the starting number the invoices will begin from. The next invoice you create will have the new invoice number.
Set the invoice prefix e.g. IN#. Invoice ID's will start at IN#1 for each unique prefix.