A TurboTax Online account can only be used for one tax return. To file a tax return for your daughter you will have to create a new separate TurboTax Online account for her. You can use your email address for her account.
It would probably be less expensive to use the TurboTax Desktop software instead of TurboTax Online. You could file both your own tax return and your daughter's tax return with one copy of the desktop software.
By the way, as Bsch4477 pointed out, your daughter will have to pay "kiddie tax." When preparing her tax return you must go through the "Child's Income (Under Age 24)" section of the TurboTax interview.
