@Sashajade75
If you do nothing now, then when you file your return, you would get a larger than normal refund, because the child tax credit is increased from $2000 to $3000 or $3600 depending on the age of the child.
The IRS has indicated they will allow parents in your situation to enroll in the advance payments, which would be $300 per month starting in July or August (whenever they get their act together). This does not change your credit or refund, it only changes when you get the money. (Advance payments will reduce your refund.). The IRS site to enroll in advance payments is not ready yet, but will be here when it is ready.
https://www.irs.gov/credits-deductions/advance-child-tax-credit-payments-in-2021
If the other parent does nothing now, they will probably receive advance payments. This will reduce their tax refund, and they may have to repay the advance payments if they are more than any other refund they might be allowed from normal withholding and deductions. They can unenroll from the advance payments at the IRS web site.
