ジョアーナ - Joahna gives a better approximation of how it will be pronounced in Japanese. The 'a' in Japanese is only used with the same pronunciation as the 'a' in 'awful' and it's helpful to remember that is also how the name will end.
Also the ー after the initial ア is to extend the length or duration of that vowel sound.
Joanna is written as ジョアナ (joana) in Japanese.
ジョアナ (Jo-a-na)
The meaning of the name Joanna is 'God is gracious'.
Johanna is originally based on the name Joanna, which ommits the h. Joanna means 'God is gracious'. Source: Wikipedia
"Olga" is not a Japanese word or name, so it doesn't mean anything at all in Japanese. Did you mean, "What is the name "Olga" translated to in Japanese?"
Joanna Roth's birth name is Angelis, Joanna.
Joanna Jimenez's birth name is Joanna Jimenez.
Joanna Angel's birth name is Joanna Mostov.
Joanna Crawford's birth name is Joanna Warden.
Joanna Brookes's birth name is Joanna Sims.
Joanna Wiszniewska's birth name is Joanna Milobedzka.
The name Michelle does not mean anything in Japanese, but can be written: ミシェル
JoAnna Cameron's birth name is JoAnna Kara Cameron.
Joanna Lumley's birth name is Lumley, Joanna Lamond.