18 year old dependents are not supposed to receive stimulus checks. At the age of 18 she can be claimed as a dependent on her parents' return. You did not receive stimulus #1 or #2 for her because parents got those stimulus checks for children under the age of 17 at the end of 2020. She was too old so under the tax law you could not receive a stimulus check for her--it followed the same age limit that is applied to the child tax credit. The age limit has changed for the 3rd stimulus, and you can get the $1400 for her if you claim her as your dependent on your 2020 return.
If you do not claim your daughter as a dependent and she files her own return saying that she CANNOT be claimed---you are encouraging her to file an incorrect return----unless you do not pay for over half her support, which is unlikely.
https://ttlc.intuit.com/community/dependents/help/when-do-i-have-to-answer-yes-to-being-claimed-as-a...
But if you want to find the place in the software to enter stimulus money received. use the Federal Review section. There is a tab on the top of your TT tool bar called Federal Review.
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
