You don't add your childs income to your return. If they need to file a return you would create an account for them. If you use your account, your childs information would overwrite yours. If your childs files his own return, he would check that someone else can claim him/her on their return.
Do I need to file my own taxes if I'm a dependent?
https://ttlc.intuit.com/replies/3302185
If the child qualifies as your dependent, you would not claim your dependent's Form W-2 on your own tax return.
The dependent will need to file their own return if they are required to file, or if they would like to receive any refund that they are due. If the dependent files their own return, they will need to indicate that they can be claimed as a dependent by someone else. To determine if the dependent is required to file a tax return to report their income, please see the following TurboTax FAQ:
You don't add your childs income to your return. If they need to file a return you would create an account for them. If you use your account, your childs information would overwrite yours. If your childs files his own return, he would check that someone else can claim him/her on their return.
Do I need to file my own taxes if I'm a dependent?
https://ttlc.intuit.com/replies/3302185