When selling products, you can use a usb barcode scanner to add them to an invoice. This reduces the chance of errors at check out.
First, you will need to add the product barcode to your product:
Go to admin/products and click the name of the product.
In the General section, click "Add barcode"
Place the cursor in the barcode field and scan your product. The barcode number will fill the field and the changes will be updated.
When selling your product:
Go to POS and then click in the Product field of the Add invoice item section (at the bottom of the invoice on the left hand side).
Scan your product and the barcode will populate the field. The system will search for the product and the name will replace the barcode.
You can have more than one barcode for each product. This is useful if you receive stock of a new updated version of a product whilst still holding some of the old one.
The most commonly used barcode format in the world is the EAN-13 barcode. If you are creating your own barcodes, choose this format.