This one has been asked recently.
One presumes that you know Junko quite well, so there is no need for formality, of which there is lots in Japanese. But limiting ourselves to expressions used when speaking to friends.

Junko ha genki ka, = (Are you) well, Junko?

Junko ha Genki? = same as above ("ka" is like a question mark)

Junko, saikin do? = How have you been recently?

Junko ha ? = Junko is...

(Hi) Junko, choushi dou?
Hi = English, but everyone recognises it. Choushi do? Literally "How is (your) condition"

Junko, Dougenshon? Mid Kyuushu dialect for how's things? Not to be used for non mid-Kyushu people. Kyushu is the southern Island in Japan.

Junko, moukarimakka? Oosaka dialect for "Junko, are you making money?" This may be used for "how are you?" in Oosaka, as a sort of cliche'

"Junko ha dou ka?" If you have said how you are, then afterwards you could say, this meaning, "How is Junko?" If you have not said how you are, then the "how" (dou) could refer to other things than the Junko's state of mind and body, so it is difficult to begin with this.

douどうis impolite and enough expression, but a polite is doudesukaどうですか, and another polite (feminine also) is ikagaいかが or ikagadesukaいかがですか.