If you have filed your return & it was accepted, you need to amend your return to add your W2's. Amended returns must mailed.
How do I amend a 2016 return in TurboTax?
https://ttlc.intuit.com/replies/5114064----------------------------------------
If you have not filed your return yet or it has been rejected go back to Federal taxes tab, Wages and Salaries, to add your W2's.
