게 쓰이다

be used, or be written

쓰이다 is the passive of two different 쓰다 verbs, and both appear here. "Be used": 유용하게 쓰이다 and 요긴하게 쓰이다 both mean "come in handy", while 방만하게 쓰이다 is money being spent recklessly. "Be written": 빼곡하게 쓰여 있어요 "it's written all over, packed tight", 그렇게 쓰여 있어 "that's what it says". The 있다 is your clue — 쓰여 있다 is nearly always the writing sense.