。
She turned off the radio.
Literal
[topic-は] radio [object-を] turned-off.
消す is the transitive verb for 'to erase, extinguish, turn off' — paired with its intransitive counterpart 消える ('to disappear, go out'). The same verb covers many extinguishing senses: 火を消す (put out a fire), 電気を消す (turn off the lights), 文字を消す (erase letters). Japanese has many such transitive/intransitive verb pairs (called 自動詞・他動詞), and choosing between them is a major learning curve for beginners.