how to do I add a w2 for my teenage child? when I try to add a W2 it does not show my child as an option to who it belongs to

[DoninGA]

You do Not enter a child's earned income from work reported on a W-2 on your tax return.

The child can file their own tax return and get a refund of any taxes withheld.  If they do fil a tax return make sure that they indicate on their return that they can be claimed as a dependent.