If my college student who made less than $6000 doesn't file taxes, how does she get the tax money paid returned to her?

With less than $6,000 in income you are not required to file a tax return.  However, you should file a return if it is to your benefit to do so.

To get a refund for taxes withheld, your college student needs to file a tax return.  She can file a tax return even if you are claiming her as a dependent.  She must indicate in the personal information section that someone else can claim her as a dependent.

Because her earnings are less than the standard deduction of $6,300, she should receive a refund of the federal income taxes withheld.  Social security taxes and medicare taxes withheld are not refundable. She may also be required to file a state tax return.