。
Where does she live now?
Literal
She [topic-は] now where [at-に] is-living [question-か]?
どこ is the wh-word for 'where,' attached to に to form 'in/at where' for residence. 住む takes ~ている for ongoing residence — there's no other natural form. Question-final か is mandatory in polite questions; in casual speech, it's often dropped in favor of rising intonation. The wh-word stays in place — Japanese doesn't move it forward, in contrast to English 'where does she live?'