She might have to file a tax return. What kind of income does she get? Did she get a W2 or a 1099Misc or 1099NEC?
If she only got a W2 for under 12,200 she doesn't have to file except to get back any withholding taken out. If it is more or she got a 1099Misc or 1-099NEC for any amount you do have to file a return.
Be sure on her return you check the box that says someone else cam claim you That is VERY important!
Filing requirements for a Dependent
https://ttlc.intuit.com/community/children-dependents/help/do-i-need-to-file-my-own-taxes-if-i-m-a-d...
