Prior year tax returns can only be printed and mailed, they cannot be e-filed.
If you did not request an extension for tax year 2014, it is to late to file for a 2014 tax refund. It had to be filed on or before April 15, 2018.
Go to this website for to purchase, download and install on a personal computer for prior tax years (2016 thru 2014) - https://turbotax.intuit.com/personal-taxes/past-years-products/
You have up to three years from the original due date of the tax return to file for a tax refund.