Code One is a square 2D barcode, recognizable by the bars across its middle. Besides the usual versions, it comes in two short, wide ones for a narrow space. Check that your scanner reads it before you print a batch.

What it holds
Characters	Letters, digits and symbols, and the accented letters of Western European languages - é, ü, ñ and the like. The euro sign, other alphabets and emoji don't fit: use a QR Code for those.
Length	Up to 3,549 digits or 2,217 letters.
Error correction	Built in, and set by the size: there's nothing to choose.
Readable text	None.

Settings
Size	Automatic size picks the smallest version the value fits. A to H are the versions from the smallest to the largest. S and T are short and wide, for a narrow space: S holds digits only, up to 18; T up to 88 digits or 55 letters. When the value doesn't fit the size you chose, Labeljoy uses a bigger one.
Encoding	Standard or GS1: see GS1 and HIBC data.

Characters you can't type. With Encoding set to Standard, a tilde followed by three digits is the character with that code - ~013 is a carriage return - and ~~ is a tilde.

The rest of the settings - quiet zone, color - are in the Barcode section.

What goes wrong
Input data too long for symbol.	The value doesn't fit even the largest Code One, version H.
Only Latin-1 characters, the letters of Western European languages, fit in this barcode.	The value has a character Code One can't hold - a euro sign, another alphabet, an emoji.