TurboTax was asking for me to enter my dependent child's income. I put 0 because I didn't have it but now that I have it, I can't find where to enter it? Why do i need?

TurboTax was prompting me to enter my dependent child's income but i didn't have it handy. Now that I have it, I can't find where to enter it in TurboTax.  Can you help me find the right spot?  I'm also wondering why it needs to be entered?  I'll be filing a tax return for her separately.