Choosing a barcode format

Code 128 is flexible: letters, numbers, and symbols for stock codes and asset tags. EAN-13 is 13 digits with a check digit for retail products. If you have a 12-digit UPC, prefix it with 0 and use the EAN-13 tab, or read why that works in the Code 128 vs EAN-13 guide.

Leave quiet space on both sides of the bars, keep contrast high, and do not shrink the height until a test scan succeeds.