I have noticed on the older SharePoint online it is possible to use barcodes within a column in Lists, however on the 'format this column' option that is no longer an option ?
Barcodes are available with the "In Place Records Management" feature. You can activate in Site Collection Administration > Site Collection Features > In Place Records Management.
Within List Settings > Information management policy settings > Item > Enable Barcodes.
Add the "Barcode" column to your view and it will show up.
I hope this helps.