A separate return will need to be filed for your child to report the 1099 MISC income. Note that self-employment taxes will be due on the 1099 MISC income.
To start a new return in TurboTax online see below:
https://ttlc.intuit.com/replies/3288574
To enter a 1099 MISC form, see the steps below:
https://ttlc.intuit.com/replies/4770594
