My son just started working, he is 15. I still claim him. Does he put zeros across all lines on w-2?

[TomYoung]

No, he prepares his own income tax return, entering the W-2 completely, and possibly getting a refund of most or all of his tax.  Assuming that you continue to provide more than half of his support then you continue to claim him as a dependent.  He, on his own income tax return, notes that he is claimed as a dependent on someone else's income tax return.

[SweetieJean]

I wonder if OP is really asking about a W-4 form.