The following link will provide help for prior year's returns through TurboTax:
https://turbotax.intuit.com/personal-taxes/past-years-products/
(if you want to prepare on paper for free: )
You can download the Forms and Instructions from the IRS web site:
https://www.irs.gov/forms-pubs
Remember to prepare your state return as well—if you live in a state that has a state income tax.
You can amend returns that have been accepted by the IRS. If your return is pending, you won't be able to make any changes until it's accepted or rejected by the IRS. If you don't know your e-file status, we can help you check it.
Select a tax year for specific amending instructions.
Keep in mind: You have 3 years from the date you filed your return (or 2 years after you paid the tax due, whichever is later) to file an amended return, which means you don't have to get it done by the April 15 filing deadline.