TurboTax does not have your child's Social Security number. As the parent you are supposed to keep that on record. You can get it from a past tax return or from a transcript of a tax return if you claimed the child as a dependent on a previous return.
Access to prior year returns.
https://ttlc.intuit.com/questions/3402465-how-do-i-access-my-prior-year-2016-or-earlier-return
You can get a free transcript from the IRS:
https://www.irs.gov/individuals/get-transcript
How do I get a copy of a return I filed using online TurboTax?
https://ttlc.intuit.com/questions/1900748
How do I get a copy of a return I prepared using desktop TurboTax?
https://ttlc.intuit.com/questions/1900639
How to upgrade to PLUS
https://ttlc.intuit.com/questions/3404582-how-do-i-upgrade-to-plus-if-i-already-filed-my-2016-tax-re...
https://ttlc.intuit.com/questions/3796106-why-do-i-have-to-pay-to-access-my-prior-year-return
https://ttlc.intuit.com/questions/3355524-when-does-access-to-my-prior-year-turbotax-online-returns-...
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
