Worked example
An inventory sheet with rows SKU-1042,Blue mug and SKU-1043,Red mug produces two independently labeled codes after CSV export.
Before you print
This tool reads CSV, not native .xlsx files. Export UTF-8 CSV from Excel and check the preview before printing.
Barcode artwork is not proof of an assigned GS1 number. A free barcode image and a GS1-issued GTIN are different things.