My daughter was 17 at the endof 2019 and is graduating high school in May 2020. How do I enter her information to claim the child tax credit

[DoninGA]

Since she was age 17 in 2019 then she is no longer eligible for the child tax credit on a 2019 tax return.  She is eligible for the Other Dependent credit of $500.

[Hal_Al]

This comes as a big surprise to many parents the year their child turns 17. A child over age 16 no longer qualifies for the Child Tax credit (CTC). Although a child can still be a student dependent through age 23, and a qualifying child for EIC,  the Child Tax Credit expires the year they turn 17 and you no longer get the $2000 CTC. Instead you will get the non-refundable (up to) $500 Other Dependent Credit.