There is no credit called the "child income credit." Are you asking about the child tax credit? The child and dependent care credit? Or earned income credit?
https://ttlc.intuit.com/questions/1900923-what-is-the-child-tax-credit
https://ttlc.intuit.com/questions/1900643-what-is-the-child-and-dependent-care-credit
https://ttlc.intuit.com/questions/1899157-what-are-the-qualifications-for-the-earned-income-credit-e...
https://www.irs.gov/credits-deductions/individuals/earned-income-tax-credit/use-the-eitc-assistant
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