The IRS is requesting that you prove that the child you entered on your tax return lived with you, was related to you and was a certain age for EIC purposes.
See this IRS website for Form 886-H-EIC - https://www.eitc.irs.gov/EITCCentral/f886-h-eic.pdf
As stated on the form -
"We must have proof for all three: you are related to the child, the child lived with you and the child's age. If you don't have or can't get the legal documents that we ask for, you can't claim EITC with that child. But, you may still be eligible for EIC without a qualifying child."
The IRS is requesting that you prove that the child you entered on your tax return lived with you, was related to you and was a certain age for EIC purposes.
See this IRS website for Form 886-H-EIC - https://www.eitc.irs.gov/EITCCentral/f886-h-eic.pdf
As stated on the form -
"We must have proof for all three: you are related to the child, the child lived with you and the child's age. If you don't have or can't get the legal documents that we ask for, you can't claim EITC with that child. But, you may still be eligible for EIC without a qualifying child."