Add a Barcode to a PDF

Code 128 holds ordinary keyboard characters and is the usual choice for internal references, asset tags and document control numbers. Bars are drawn as vectors rather than as an image, which matters for scanning: a barcode rendered at screen resolution and printed often will not read. Only Code 128 is offered, because a format that half works is worse than one that is absent.

Which formats are supported?

Code 128 B, which covers ordinary keyboard characters. Others are not offered rather than offered badly.

How small can it be?

Below about 30mm wide many scanners struggle. Test before printing a batch.

Is anything sent anywhere?

No. The barcode is encoded in your browser.