If it shows a federal tax due then she needs to file federal. Why does it have a tax due? What kind of income does she have? Just a W2 or did she get a 1099NEC? You have to file a 1099NEC for any amount. Did she have any interest, dividends, or investment income?
Also the Standard Deduction for a dependent can be less than the full Standard Deduction. It only covers W2 and 1099NEC income. So if she has other income she might owe tax on it.
