。
She left her ticket at home.
Literal
She [topic-は] ticket [object-を] home [at-に] left-forgot.
置き忘れる is a compound verb: 置く (to put/place) + 忘れる (to forget) = 'to leave behind' or 'to forget somewhere.' The compound captures the two-part nature of the mistake — she put the ticket down and then forgot about it. 切符 (きっぷ) is a ticket, typically for trains or buses.