You were getting two different provisions of the new American Rescue plan law mixed up.
First, there is a $1400 per person stimulus payment, that includes dependents. The IRS has not announced how they will pay this yet.
Second, there is an expanded child tax credit. This takes effect July 1, and is to be paid directly to taxpayers monthly, or as often as the IRS can make practical, rather than having it included on any tax returns. The IRS has also not released any information about how they plan to make these payments.
The stimulus link provided by pattif12 also includes information on the expanded child tax credit.
Expanded Child Tax Credit
Starting in tax year 2021, the Plan increases the Child Tax Credit from $2,000 to:
- $3,600 for each child under 6
- $3,000 for each child age 6–17
It also makes the credit fully refundable, meaning you’ll be eligible to get it even if you don’t owe taxes.
Starting in July, payments for the Credit will be sent in advance so you won’t have to wait to file your 2021 taxes to receive that amount.
You don’t have to do anything to get these payments. The IRS will likely determine eligibility based on your most recent tax filing.
In particular, getting the new (expanded) child tax credit has nothing to do with filing your 2020 tax return. Whether you already filed, file now or file later, the additional money will not be part of your 2020 tax refund.