。
She made coffee for us.
Literal
She [topic-は] us [to-に] coffee [object-を] brewed for-us.
コーヒーをいれる ('to make coffee,' literally 'to put in coffee') uses いれる (to put in / brew) — the standard verb for preparing brewed drinks. The same いれる covers tea: お茶をいれる. Note that 作る ('to make') is not normally used here; the action is specifically about brewing or steeping. With ~てくれる, the gesture becomes a small but warm act of hospitality. The polite ~ました fits a recounted social moment.