To e-file your 2017 taxes, the IRS requires your 2016 AGI (Adjusted Gross Income) for identity verification. If you didn't file 2016 taxes; in that case enter 0 as your AGI. If you did file last year, here are some options on how to obtain your AGI:
https://ttlc.intuit.com/replies/3301618
If you are still unable to e-file, you can print and mail in your return.