In conversion "調子はどう?" (choushi ha dou?) or "元気～？" (genki~?) But Genki~? is so casual expression. So of course we shouldn't use at exam or for superior. In letter or mail "元気にしてますか？orお元気ですか？"(genkinishitemasuka or ogenkidesuka?)
We don't have any rules when we use it. But most of Japanese people separate like so.
This answer is brought to you by the high school student from Japan. So don't use too much reference.
The Language Level symbol shows a user's proficiency in the languages they're interested in. Setting your Language Level helps other users provide you with answers that aren't too complex or too simple.
Has difficulty understanding even short answers in this language.
Can ask simple questions and can understand simple answers.
Can ask all types of general questions and can understand longer answers.
Can understand long, complex answers.
This answer was given within 60 minutes of the question being posted.
How do you say "Hello" in Korean? Find out on HiNative!