Can an independent contractor file taxes on dependents and receive a return amount. Or is this only for W2 employees?

If I am doing DoorDash, or real estate agent or rover. Can I file dependents and receive a return amount for them? I have three kids. If I can do this will I need to make a certain amount? I heard if you make over 600 as independent contractor you have to pay money back to IRS. Is that true?