A BARCODE is a square or rectangular image made of a series of parallel black lines and white spaces of varying widths. 

BARCODES can be read by an optical barcode scanner and are applied to products for quick identification. 

They are used in retail stores as part of the purchase process, in warehouses to track inventory, and on invoices to assist in accounting, among many other uses.

Keep in mind the BARCODE field is optional on Product Pages and you don’t have to fill it in if you don’t want to.