Sorry no, you can not do 2017 online. Online is only good for 2018.
Yes you will have to mail the 2018 1040X Amended return.
And mail the 2017 original return.
When you mail a tax return, you need to attach any documents showing tax withheld, such as your W-2’s or any 1099’s. Use a mailing service that will track it, such as UPS or certified mail so you will know the IRS received the return. Don’t forget state.
Important! Mail Federal and State in separate envelopes and mail each year in separate envelopes. So you might have to mail 4 separate envelopes.
