。
She lives in Yokohama.
Literal
She [topic-は] Yokohama [in-に] is-living.
住む is a change-of-state verb — the act itself is 'taking up residence,' which happens at one moment, so 住む alone in plain present sounds like 'will move there.' To express the ongoing reality of 'currently lives there,' Japanese uses 住んでいる, the resulting state of having taken up residence. This is the same pattern as 知っている ('knows' = is in a state of having learned) and 結婚している ('is married' = is in a state of having gotten married). Yokohama, just south of Tokyo, is Japan's second-largest city by population and was one of the first ports opened to foreign trade in 1859, giving it a famously cosmopolitan flavor — Chinatown, Western-style architecture, and a waterfront skyline.