Johanna is the German feminine of Johannes (John) — from the Hebrew Yochanan ("God is gracious"). Johanna Spyri (1827-1901) — Swiss author of Heidi (1881) — among the best-selling books in the history of literature, with 50+ million copies sold across 50+ languages and continuous adaptations in film, TV, and stage for 140+ years; the title character's journey from her grandfather's Alpine cabin to the Sesemann household in Frankfurt and back has shaped generations of children's literature worldwide. Johanna Bordon — Mexican gymnast; Sydney 2000 Olympics. Johanna Petrini — Italian basketball player. Johanna Doderer — Austrian composer. Saint Joan of Arc's mother was Isabelle Romée; Joan herself in Latin is Iohanna — so Johanna shares the Latin liturgical form with the patron saint of France.
Johanna does not currently appear in the US Social Security Administration's top 1,000 girls' names, so we don't publish a US rank or birth count for it. That says nothing about the name's standing elsewhere in the world — only that it sits outside the ranked US data we rely on.
In Pythagorean numerology the letters of Johanna reduce to 9, The Giver. This is a traditional interpretive system, not a factual claim about the name.