Judith is not in the Tanakh and no ancient Hebrew text of it survives, which is a striking pair of facts given how thoroughly Jewish the book is. It kept a place in Jewish memory by another route. Medieval Hebrew retellings circulated, in several of which Nebuchadnezzar is replaced by Antiochus and the setting moved openly to the Maccabean revolt, and these became attached to Hanukkah: read in some communities on the Sabbath of the festival, and cited as a reason for the custom of eating dairy at Hanukkah, since in those retellings Judith feeds the general salty cheese to make him drink.
In Christian use the book came through the Septuagint and was cited early; Clement of Rome holds Judith up as an example of courage within a century of the Gospels. The Council of Trent defined it as canonical in 1546, and the Orthodox churches receive it. The reformers placed it in the Apocrypha, where the King James translators printed it and from where later Protestant Bibles generally dropped it, so that most English-speaking Protestants now encounter the story only through art.
That afterlife dwarfs its canonical standing. Donatello's bronze Judith and Holofernes was set up in Florence as a republican emblem against tyranny. Botticelli, Mantegna, Cranach, Caravaggio, Rubens and Klimt all took the subject up, and Artemisia Gentileschi painted the beheading twice, with a physical directness, two women pinning a struggling man and working the blade, that has kept the pictures in argument ever since. The image of the woman with the sword and the severed head is far better known than the text that produced it.