She withdraws $500 from her bank account.

withdraws 是动词 withdraw 的第三人称单数现在时形式。withdraw 由前缀 with-（表示"向后、离开"）和动词 draw（拉、取）组成，字面意思是"向后拉/取回"，引申为"提取（钱款）、撤回"的意思。