I did not recieve a stimulus check for my son last year, I forgot to put that down when asked about my stimulus, how can I go back and edit this information?

Did you file yet?  Actually you don't put down that you did not get it.  You enter what you actually got and if you qualify for more it is added to 1040 line 30.  Did you claim your son as a dependent on your return?  

If you haven't filed yet......

The Stimulus checks are really based on your 2020 tax return. Any amount you already got will be reconciled on your 2020 return line 30. If you didn't get a Stimulus Check (and qualify) or you qualify for more it will be added to your 2020 return. But the good news is if they paid you too much they won't take it back.

When you go through the federal review tab it will ask how much you got if any. Or to enter your stimulus payment in TurboTax, type "stimulus" (without the quotes) in the Search box, then click the link that says "Jump to stimulus." If you didn't get one or both enter a 0 and not leave it blank or it won't calculate it.

After you have entered your tax information and are ready for the Federal Review, it will be the first question.

If you are trying to trigger it, you can go to Other Situations, answer any questions and click Done. The next automatic selection is Federal Review and it will ask about payments received.