If the child is not related to you but she lived with you all year, and you paid for over half her support, you may be able to claim her for the $500 credit for other dependents. Since she is not your child and is not related, she cannot be a qualifying child, you cannot get child tax credit, earned income credit or head of household filing status by claiming her. She might be a "qualifying relative" dependent for you----despite the name, she does not have to be a blood relative.
WHO CAN I CLAIM AS A DEPENDENT?
You can claim a child, relative, friend, or fiancé (etc.) as a dependent on your 2024 taxes as long as they meet the following requirements:
Qualifying child
- They're related to you.
- They aren't claimed as a dependent by someone else.
- They're a U.S. citizen, resident alien, national, or a Canadian or Mexican resident.
- They aren’t filing a joint return with their spouse.
- They're under the age of 19 (or 24 for full-time students).
- No age limit for permanently and totally disabled children.
- They lived with you for more than half the year (exceptions apply).
- They didn't provide more than half of their own support for the year.
Qualifying relative
- They don't have to be related to you (despite the name).
- They aren't claimed as a dependent by someone else.
- They're a U.S. citizen, resident alien, national, or a Canadian or Mexican resident.
- They aren’t filing a joint return with their spouse.
- They lived with you the entire year (exceptions apply).
- They made less than $5050 in 2024 (not counting Social Security)
- You provided more than half of their financial support
IRS interview to help determine who can be claimed:
https://www.irs.gov/help/ita/who-can-i-claim-as-a-dependent
https://ttlc.intuit.com/questions/3113432-who-can-i-claim-as-my-dependent
CREDIT FOR OTHER DEPENDENTS
https://ttlc.intuit.com/questions/4499708-what-is-the-500-credit-for-other-dependents-family-tax-credit