Learn Portuguese (Portugal): Onde é que moras?

The phrase é que literally means "is it that". In Portuguese questions, it acts as an optional filler to emphasize the question word and make the sentence sound more natural. You could simply ask Onde moras?, but adding é que is extremely common in spoken Portuguese.

Where is the word for "you" in this sentence?

The "you" is built into the verb itself! Moras is the informal "you" form of the verb morar (to live). Because the -as ending already tells us the subject is the informal "you" (tu), the actual pronoun is usually dropped to sound more natural.

Why use moras instead of a form of viver? Don't they both mean "to live"?

They do both mean "to live", but morar is used specifically for your physical residence or address, much like "to reside" in English. Viver is broader and refers to the experience of living. To ask about a home or city, morar is the most precise and common choice.

Why is it Onde and not Aonde?

You use Onde when asking about a fixed location, like where you live. Aonde translates to "to where" and is only used with verbs of movement, such as asking where someone is traveling to.