How do i obtain a 2015 tax year basic 1040ez addition

[Carl]

You have to purchase the CD/download and physically install it on your computer. You can't do a prior year return with the online version. You also can't e-file a prior year's return, because the IRS says you can't. You have to print it, sign it, and mail it to the IRS. You can get whatever flavor of TurboTax 2015 you desire at https://turbotax.intuit.com/personal-taxes/past-years-products/  

Note that after you pay for it, you can download the CD installation file and install it immediately, so you don't have to wait for the CD to come in the mail. Also understand that if in addition to downloading it, you also want a physical CD mailed to you, then you have to specifically select that option during the purchase process.  Also, make sure you're under the correct tab on that page, for the tax year you want. TurboTax only supports their program for the current tax  filing year, and three years back.