the question what relation are they to you there. two other questions if your child quailifes one checks credit for other dependents. why wouldn't. that child quality

You cannot get the child tax credit for a child older than 16.   If your child was older than 16 at the end of 2023, you get the $500 child tax credit for that child instead of the child tax credit.    And...you only get the child tax  credit for your own bio-child---not the child of a GF or BF.   If one of the children is the child of a BF or GF, you get the $500 credit for other dependents.   Also....the child must have a Social Security number or you cannot get the CTC.

https://ttlc.intuit.com/questions/1900923-what-is-the-child-tax-credit

https://ttlc.intuit.com/turbotax-support/en-us/help-article/taxation/additional-child-tax-credit/L6xFeMFEf_US_en_US?uid=lqnuygah

https://www.irs.gov/help/ita/does-my-childdependent-qualify-for-the-child-tax-credit-or-the-credit-for-other-dependents

Look at your 2023 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 19

Credit for Other Dependents line 19

Earned Income Credit line 27

Additional Child Tax Credit line 28