While this seems to apply to a good amount of people, it seems the IRS has an informative enough page https://www.irs.gov/credits-deductions/individuals/earned-

While this seems to apply to a good amount of people, it seems the IRS has an informative enough page https://www.irs.gov/credits-deductions/individuals/earned-income-tax-credit-eitc https://www.irs.gov/credits-deductions/individuals/earned-in... However, it is most likely that the people claiming EITC are the least likely to understand the information there