。
She trained as a singer.
Literal
She [topic-は] singer [as-として] training [object-を] received.
訓練を受ける = 'undergo training,' literally 'receive training.' The verb 受ける ('receive') is highly productive in Japanese with abstract objects: 試験を受ける ('take a test'), 影響を受ける ('be influenced'), 治療を受ける ('receive treatment'). It's often the natural way to render English's 'undergo' or passive-flavored 'be subject to.' The sentence describes her formal preparation rather than a casual hobby — 訓練 carries connotations of structured, sustained training of the kind one would undertake at a music conservatory.