If she was an employee and received a W-2 and had taxes withheld she should file a tax return to get a refund of the taxes. If she does file a return make sure that she indicates on the return that she can be claimed as a dependent.
If there were no taxes withheld from her wages on the W-2 there is no reason to file a return since she is below the filing requirements based on her income.
However, if her income was from self-employment then she is required to file a tax return since the income was $400 or more and file a Schedule C for her self-employment income and expenses.
