You cannot file a 2017 8606 in 2018.
The 8606 is automatically created when a Traditional IRA contribution is entered in the IRA contribution interview section and is either non-deductible because of high income phase out or manually made non-deductible by answering the interview questions.
It is not necessary to amend to report a non-deductible Traditional IRA contribution since the 8606 can be filed by itself if it was not part of your tax return.
Enter the 2017 contribution on line 1.
If you had any other carry-over nondeductible basis from previous years enter that on line 2.
Put the total of lines 1 & 2 on line 3 & 14.
You can download the form and instructions from the IRS.
Where to mail: https://www.irs.gov/uac/where-to-file-paper-tax-returns-with-or-without-a-payment