How do you write how you doing in polish?

Answer 1

Literally you want to ask "How do you have yourself?".

In a formal situation you would ask "Jak pan miewa?" to a man or "Jak pani miewa?" to a woman.

If you were on more familiar terms with somebody, you would ask "Jak się masz?".

If you mean it as a type of greeting and are not interested in a response, you could instead say "Miło mi!", which translates roughly as "It is nice for me [to see you]."