。
She left a note for me.
Literal
She [topic-は] me [to-に] left-note [object-を] did.
置手紙 (おきてがみ) literally 'placed-letter' is a fixed compound for a note left behind for someone — typically when the writer can't deliver the message in person. Distinct from 手紙 (a posted letter): 置手紙 is set down on a table or pinned to a door for the recipient to find. The verbal collocation 置手紙をする ('do a note-leaving') treats the action as a one-shot event. In modern usage texting has displaced most everyday cases, but 置手紙 still carries a literary, slightly old-fashioned warmth — the kind of note left by a parent for a child, or by a roommate slipping out early.