You can't correct the child tax credit directly in TurboTax, as it is a function of other entries on your tax return, such as your income and the number and age of your dependents.
You need to understand that your Child Tax Credit, which is normally $2,000 per child under age 17, can only be used up to the amount of your income tax. Some, but not necessarily all of the remaining credit can sometimes be used as an Additional Child Tax credit.
So, it may be that your child tax credit is correctly stated on your tax return, but you believe it is wrong because it is less that expected amount of $2,000 per child.
You will see the child tax credit on line 19 of your form 1040, and the additional child tax credit on line 28.
I got a letter saying I was still owed 1800 for it. How do I claim it now,my taxes have been filed
I forgot to enter the amount of AdvCTC payments received in 2021 to the 8812 form, line 14f. As a result, my return amount significantly changed. How do I fix this discrepancy?
You do not need to do anything. The IRS will adjust your return appropriately for your ACTC payments when they process it.