You must be asking about the increased child and dependent care credit. You do not necessarily "receive" $8000 per child. You can get credit on your tax return for up to $8000 per child if you paid someone to take care of your child while you worked. For 2021 tax returns the credit is a refundable credit, but if you paid less than $8000 per child for the daycare, you will not get more back than you paid, nor will you get back more than you earned from working.
The FAQ below explains the credit for 2020----for 2021 the amount is increased.
Form 2441 is the credit for child and dependent care expenses. You must have a qualifying child dependent, usually your own child under the age of 13 who lives with you more than half the year. You must pay for daycare so that you (and your spouse if married) can work. You must provide the name, address, and Social Security number or tax ID number of the daycare provider. You can claim up to $8000 of qualifying expenses per child, or up to $16,000 for two or more children, but only if you actually paid daycare expenses so that you could go to work. You would receive a credit of between 20% and 50% of your actual expenses, depending on your income. The credit percentage is a sliding scale that starts at 50% and is then reduced for higher income taxpayers. If you are using TurboTax, there is a section on the deductions and credits page to enter your daycare expenses and they will automatically be put on form 2441.
Note that this is an enhanced credit for tax year 2021 only. For 2022, the child and dependent care credit will return to its normal level which was up to 35% credit for up to $3000 of daycare expenses for one child or $6000 of daycare expenses for two or more children.
Note that $8000 is not the amount you get. It's the maximum amount of child care expenses that can be used to calculate the credit.
The highest credit amount available for this tax year is $4,000 if you have just one child and $8,000 for two or more children. Not everybody gets that much.