Have you located the 2016 return, but access is locked, and it asks you to pay? If so, we can tell you how to upgrade a 2018 Free Edition return to PLUS and pay the 19.99 by credit/debit card to unlock the prior returns.
Have you already started a 2018 return, and if so, in what edition? And is the 2016 return in the SAME account as your 2018 return?
Be aware there's a free option if a tax return transcript would suit your purpose. You may be able to immediately download a 2016 return transcript at this IRS website at the link below. If you don't qualify to open a free IRS account there, you can order one to come by postal mail, which normally takes 5-10 calendar days.
<a rel="nofollow" target="_blank" href="
http://www.irs.gov/Individuals/Get-Transcript">http://www.irs.gov/Individuals/Get-Transcript</a>
