。
She used up all the paper.
Literal
She [topic-は] paper [object-を] used-up.
使い果たす is a compound verb formed from 使う ('to use') + 果たす ('to fulfill, accomplish, exhaust'). The auxiliary use of 果たす in compound verbs adds the sense of 'doing X completely / exhausting the supply' — 食い果たす ('eat through everything'), 売り果たす ('sell off completely'). Compound verbs like this are everywhere in Japanese and are one of the language's most productive ways of building precise meanings out of pairs of native verbs. Compare with the more common 使い切る ('use up entirely'), which uses 切る ('cut') as the second component for the same general sense.