Did I have to fill out another form for the Additional Dependent Credit for my 17 year olds

[JamesG1]

The Child Tax Credit and the Additional Child Tax Credit are both computed on IRS form 8812 Additional Child Tax Credit.

As you answer the TurboTax interview questions, the proper calculations are made on the form.

[xmasbaby0]

Look at your 2019 Form 1040 to see the child-related credits you received

PREVIEW 1040

https://ttlc.intuit.com/questions/1901539-how-do-i-preview-my-turbotax-online-return-before-filing

Child Tax Credit line 13a

Credit for Other Dependents line 13a

Earned Income Credit line 18a

Additional Child Tax Credit line 18b

Child and Dependent Care Credit line 18d

[Hal_Al]

You say 17 year old.  If he had reached 17 by 12-31-19, he is no longer eligible for the child tax credit or additional child tax credit.  What you get now is the (up to) $500 "Other dependent credit".  There are no additional forms to fill out for that.  If he qualifies as a dependent, TT automatically gives you the credit on line 13a of form 1040.