Joanna is the feminine of John — from the Hebrew Yochanan, meaning "God is gracious." In Luke 8:3, Joanna was the wife of Chuza (Herod's steward) and one of the women who supported Jesus from her own means.
Joanna Newsom (born 1982) is the American harpist-singer; Joanna Lumley (born 1946) is the English actress (Absolutely Fabulous); Joanna Gaines (born 1978) is the American designer.
Joanna 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 Joanna reduce to 1, The Leader. This is a traditional interpretive system, not a factual claim about the name.