Question: Where can I get Canna stance?.Bit misleading.
You get a Pioneer Journal once you get to 50, and it will take 20 days for you to get the High master stone needed to pick Chung-ha.
She is the best dps for solo content and easier raids but kind of useless for some higher end raids as you'll just end up on the floor a lot with her.
Most end-game raid teams run some variation of Canna/Canna/Sariel or Sariel/Sariel/Canna because their range allows them to survive better and be out of the boss' range. They also top the list of magic dps and their buffs all works really well in tandem with each other.
But as a one off pick, Chung-ha is the best way to go.