。
She wears high heels to look taller.
Literal
She [topic-は] height [object-を] [high-高く] show [in order to-ために] high-heels [object-を] is-wearing.
背を高く見せる ('make oneself look tall,' literally 'show one's height as high') is a stock construction. ~ために expresses purpose ('in order to'). ハイヒール is a katakana loanword from English. はく is the right wear-verb for footwear (vs 着る for upper-body garments).