Yes, amended returns must be paper filed. Instructions for amending your 2017 will be available in late January or early February 2018.
You can't amend an e-filed return that is in the pending or rejected status. Wait until the IRS accepts the original return before mailing the amendment. Please see the FAQ below for more information, including links to instructions for amending your return in TurboTax. (Be sure to click See entire answer.)
What does it mean to "amend" a return? https://ttlc.intuit.com/replies/4204352