You do not amend your 2018 tax return for a 2017 1099-G.
You'll have to amend your 2017 tax return to add that form 1099-G.
Please see the
following TurboTax FAQ for
instructions on how to amend your tax return in TurboTax.
https://ttlc.intuit.com/replies/3288565
**Say "Thanks" by clicking the thumb icon in a post
**Mark the post that answers your question by clicking on "Mark as Best Answer"