How do I download previous year's tax returns?

When you try to download the 2016 return, does it tell you that access is locked and that you have to pay?
Are your 2016 and 2018 returns in the SAME account?   You can pay for the 2018 return in advance to unlock the prior return.  We can tell you how that doesn't involve the FILE section.

The minimum to unlock a prior return is 2018 Free Edition upgraded to PLUS at 19.99.  But you have a problem.  You appear to be using "Live Basic" which is 79.99 for a Federal return and 34.99 for a state return.    If Live Basic is the product you intend to use for 2018, we can tell you how to pay for it.

FAQ:  What is TurboTax Live?
<a rel="nofollow" target="_blank" href="https://ttlc.intuit.com/questions/3859448-what-is-turbotax-live">https://ttlc.intuit.com/questions/3859448-what-is-turbotax-live</a>

Otherwise, if you are in that "Live Basic" product by accident and only wanted Free Edition with PLUS, we can tell you how to downgrade to Free Edition.  And then how you can upgrade from Free Edition to PLUS, and pay for it a way that is easier to understand than TurboTax instructions.   You won't even need to go the FILE section with my instructions.

Thank you - finally figured it out. Had to get to the point where I could "Downgrade" THEN go back and "Upgrade" to include PLUS. What a clusterf*. Why can't there just be a way to access these files? I paid for the tax returns in the previous years which is what I'm attempting to download. Why would I have to pay for this years before getting a copy of previous years that I have already paid for? And why not make it easy for me to do that!?? So frustrating!

I agree.  We have complained about that method for 3-4 years.   We have tried to get them to just put a "pay now" button next to the prior returns, but so far no luck.

You asked:
"I paid for the tax returns in the previous years which is what I'm attempting to download. Why would I have to pay for this years before getting a copy of previous years that I have already paid for?"

You must not have used a paid edition in 2017 (PLUS or higher).   Therefore free access to prior returns expired in October 2018.
<a rel="nofollow" target="_blank" href="https://ttlc.intuit.com/questions/3355524-when-does-access-to-my-prior-year-turbotax-online-returns-expire">https://ttlc.intuit.com/questions/3355524-when-does-access-to-my-prior-year-turbotax-online-returns-expire</a>