How can I file my past 2015 taxes on turbotax?

[LinaJ2018]

To file a 2015 tax return on TurboTax, you need to purchase the 2015 TurboTax program-

https://turbotax.intuit.com/personal-taxes/past-years-products/ 

As IRS only allows e-filing on 2016 tax returns, you will need to submit your 2015 tax return by mail.