I'm confused the Internal Revenue Service has a online way to file taxes

I've been told that now 2021 2022 you can declare file a dependent on your taxes even if you are not working have no income

Is this true? I have been using my savings to provide for myself and my children. I lived with their grandfather for one year in 2020 and he filed us in his taxes 2020 he received Child Advance tax credit, the economic stimulus checks.

He received an early payment because the IRS assumed he would file the children on his taxes for 2021 he was paid $300 monthly July through December.

Now we both have no idea how to file the taxes!

The children live with me and I support them I was going to claim them this year 2021 taxes because of the new rules because I have money saved but I did not have income a job in 2021 but now they are saying I can file taxes and claim child tax credit.