Johanna is the version of this name used in Holland, Germany, and Scandinavia. The extra h makes Johanna a slightly more dignified version of Joanna.
A notable namesake is the author of Heidi, Johanna Spyri. There are Johannas in Sweeney Todd, The Hunger Games, and the Bob Dylan song, Visions of Johanna.
A Continental classic, Johanna is currently in the Top 20 in Germany, Austria and Finland.