In the COVID Tax Tip 2021-117, the IRS reminds and clarifies advance child tax credit information to the taxpayers. Note that the advance child tax credit is an early payment on potential tax credits (these are estimates) to be claimed on their 2021 tax return during the 2022 tax filing season (January to April 2022).
From this summer (2021), there will be significant changes to the Child Tax Credit. Instead of paying the tax credit when the tax return is filed (usually as a tax refund to the taxpayer), the IRS plans to make advance monthly payments beginning July 15, 2021. You will claim the other half when you file