。
She expressed her thoughts on the war.
Literal
She [topic-は] war [about-について] impressions [object-を] stated.
~について introduces the topic under discussion: 'about war.' 所感 (しょかん) means 'impressions' or 'personal thoughts' — a formal word typically found in official or academic settings. 述べる (のべる) means 'to state' or 'to express,' also formal. The combination 所感を述べる is a stiff, written-register expression; in casual speech one might say 思ったことを話した ('talked about what she thought').