* Jena: This is the most common variant, removing the "a" at the end.
* Jeanna: Adding another "a" at the end, this is more common for the name "Jean" or "Jeanne".
* Gianna: This is a different name altogether, but some might mistake it for a variation of Jeana.
* Jeane: This is more common for the name "Jean" or "Jeanne", but could be used as an alternative spelling of "Jeana".
Ultimately, the best way to spell Jeana is however the person who owns the name prefers.