I submitted my tax return on 3/3/2019, I didn't mention my daughter (7years old) as a dependent by mistake. Can I correct that information now?

[KarenJ]

Yes, you can amend your tax return to include your daughter if your return has been processed and accepted and you have received your refund (if one was due to you).

Please see the following information regarding amending your return.

https://ttlc.intuit.com/replies/3288565