As people said before, either 'De donde eres?' or 'En que ciudad vives?'
don't give too much thought to the opening question mark or the tildes ( é ), because at least conversationally, not many people use them, unless for needed words (as ones that are written the same, only varying by tilde)

word by word
De donde eres?
de = from. there are other meanings but they're more 'advanced'
donde = where
eres = comes from verb 'ser' (to be). 'eres' is second person informal way of 'ser'.

lit. from where [you] being?


En que/cual ciudad vives?

en = in, has other uses, but let's not go into that now.
que = what. in this case, if you're talking about a bunch of cities, and you're asking the listener to 'pick' one, then the best choice would be 'en cual' (from which). else, just use 'que', which doesn't have much grammatical meaning, but it's used that way.
ciudad = city
vives = from 'vivir' (to live). second person informal way

lit. in which city [you] live?