If you have a qualifying child for the Earned Income Credit (EIC), but do not claim that child as a dependent, you can still claim them for the EIC:
You can obtain additional information on the Earned Income Credit and who is a qualifying child in the IRS Instructions for Form 1040 and 1040-SR or IRS Publication 596 Earned Income Credit (EIC).
Note that any link in the information above is updated each year automatically and will take you to the most recent version of the document at the time it is accessed.