I got letter 6475, but turbo tax insists that its called something else

[xmasbaby0]

There is letter 6475 which is about the 3rd EIP payment---the $1400 per person stimulus payment sent out in 2021.   And there is letter 6419 for the advance child tax credit payments---the payments that went out between July and December to people who had children up to age 17 as dependents.   Look carefully to see which letter you have.

Letter 6475 is entered in Federal Review for the recovery rebate crdit.

Letter 6419 goes in Federal>Deductions and Credits>You and Your Family>Child Tax Credit

Either of those letters have information which you need to enter carefully and correctly or your refund will be delayed.

[VolvoGirl]

Letter 6475 is for the 3rd Stimulus Payment.  It is called the Recovery Rebate Credit on your 1040 line 30.   It is $1,400 per person and was sent out based on your 2020 return starting in March 2021.  Then you reconcile it on your 2021 return.  If you didn't get the full amount or qualify for more the extra will be on 1040 line 30.  If you are married you may each get a letter for half.  You need to enter them both or the whole amounts you received.

Make sure you enter the amounts you actually got for the 3rd stimulus so you don't claim it again. Check over your return before you file. Make sure line 30 is blank or the extra amount you did not get.

To get to the stimulus questions in TurboTax at any time, you can search for stimulus or recovery rebate credit then hit ENTER and there should be a Jump to link

If you are trying to trigger it,
Click on Other Tax Situations at top
Click on Let's get started
Answer some questions then Continue
Then click on Let's keep going
Next screen is for the Third Stimulus, if you qualify

If you did not get prompted to enter your stimulus information, that means you either:

Filed as a dependent being claimed on another tax return, or
have an AGI too high to claim the recovery rebate