I don't know about that, see section Q K5 here: https://www.irs.gov/credits-deductions/2021-child-tax-credit-and-advance-child-tax-credit-payments-topic-k-veri

I don't know about that, see section Q K5 here: https://www.irs.gov/credits-deductions/2021-child-tax-credit-and-advance-child-tax-credit-payments-topic-k-verifying-your-identity-to-view-your-payments https://www.irs.gov/credits-deductions/2021-child-tax-credit... To me it reads like Letter 6416 is meant to add specificity to "the letter" in the previous sentence. EDIT: I've found other examples of Letter 6416 online on non-IRS websites that do have a phone number at the upper right. I'm not sure if the phone number's absence from the sample PDF on the IRS website means it has been removed, or if non-sample copies would have a phone number.