The child tax credit rules for 2021 tax returns were unique to tax year 2021; you could receive the CTC even if you did not have any income earned from working. And a child could be 17 (under 18). Now the rules have gone back to the old rules. If you do not have at least $2500 of income from working you will not get the CTC or the additional child tax credit. And the age cutoff went back to under 17 (not 18).
Did you have a child turn 17 in 2023?
And.....the refundable credits are based on how much you earned from working, so if you earned more in 2022 or less in 2022 than you earned in 2023, the amounts of child-related credits will be different.
For the child tax credit---which you get for children younger than 17--
The total per child is $2000. First the $2000 is used to reduce your tax owed down to zero. When (if) your tax owed is zero, the "rest" of the $2000 can be added to your refund as the Additional Child Tax Credit----up to a maximum of $1600 per child. But....that Additional Child Tax Credit also depends on how much you earned by working.
Take the amount you earned, subtract $2500, and multiply what is left by 15%. That is your additional child tax credit ---- up to a maximum of $1600 per child.
Earned income credit is calculated on a bell curve-- so it varies according to how much you earned.
https://www.irs.gov/credits-deductions/individuals/earned-income-tax-credit/use-the-eitc-assistant
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