I file my taxes with y'all and the IRS send me a letter saying tht I need to fill the schedule 8812 form for additional child tax credit

You can prepare form 8812 with TurboTax. Follow the steps below to add the form:

 Log in to your account.

1. Go to Federal Taxes.
2. Go to Deductions and Credits.
3. Go to You and Your Family and click show more.
4. Select Child and Other Dependent Tax Credits and click Revisit.
5.  Answer any question that apply to you and navigate to the screen where it asks "If you received a letter/notice from the IRS stating you must file form 8862 to claim the Child Tax Credit" and select Yes.

This answer is flat out wrong.  The original question was about form 8812 not form 8862-  two completely different forms

It is also a year old.