What year? Sorry, Online for 2018 and prior is closed now so you can not start a new 2018 return or finish one. Online is only for 2019. Oct 15, 2019 was the last day to efile. 2018 is now the prior year.
Did you start an Online return? How to finish a prior year online return
Or How to file a prior year
You can only buy the download for prior years. You have to buy a separate program for each year. They only sell the last 3 years. You need a full Windows or Mac computer to install it on. Buy the download here
You have to print and mail prior year returns. When you mail a tax return, you need to attach any documents showing tax withheld, such as your W-2’s or any 1099’s. Use a mailing service that will track it, such as UPS or certified mail so you will know the IRS received the return. Don’t forget state.
Important! Mail Federal and State in separate envelopes and mail each year in separate envelopes.
If you are getting a refund, there is not a penalty for filing past the deadline. You have 3 years to file for a refund. If you owe taxes, the interest/penalties will be calculated by the IRS based on how much you owe and when they receive your return and payment. The IRS will bill you for this; it will not be calculated by TurboTax.
Or If you have a simple return You can fill out the blank forms for free.
Here is the IRS 2018 Form 1040
And 2018 Instructions https://www.irs.gov/pub/irs-prior/i1040gi--2018.pdf
2018 Tax and EIC Tables https://www.irs.gov/pub/irs-prior/i1040tt--2018.pdf
IRS 2018 Schedules 1 thru 6 (only if needed)
Sch 1 : https://www.irs.gov/pub/irs-prior/f1040s1--2018.pdf
Sch 2 : https://www.irs.gov/pub/irs-prior/f1040s2--2018.pdf
Sch 3 : https://www.irs.gov/pub/irs-prior/f1040s3--2018.pdf
Sch 4 : https://www.irs.gov/pub/irs-prior/f1040s4--2018.pdf
Sch 5 : https://www.irs.gov/pub/irs-prior/f1040s5--2018.pdf
Sch 6 : https://www.irs.gov/pub/irs-prior/f1040s6--2018.pdf
And I have the links for other years too.
Define "old." If you owe tax you still need to file the return and pay the tax due no matter how many years ago it is from. It is now too late to get a tax refund for any tax year earlier than 2017. You can use desktop software to prepare a 2016, 2017 or 2018 return and mail it--those years cannot be e-filed. Only a 2019 return can be e-filed, and only a 2019 can be prepared using the current online software program.
Software is not available from TurboTax for years earlier than 2016, but you can get the paper forms from the IRS site to prepare by hand and mail in.
Online preparation and e-filing for 2016, 2017 and 2018 is permanently closed.
To file a return for a prior tax year
If you need to prepare a return for 2016, 2017, or 2018 you can purchase and download desktop software to do it, then print, sign, and mail the return(s)
You may also want to explore purchasing the software from various retailers such as Amazon, Costco, Best Buy, Walmart, Sam’s, etc.
Remember to prepare your state return as well—if you live in a state that has a state income tax.
When you mail a tax return, you need to attach any documents showing tax withheld, such as your W-2’s or any 1099’s. Use a mailing service that will track it, such as UPS or certified mail so you will know the IRS/state received the return.
Note: The desktop software you need to prepare the prior year return must be installed/downloaded to a full PC or Mac. It cannot be used on a mobile device.
If you are getting a refund, there is not a penalty for filing past the deadline. If you owe taxes, the interest/penalties will be calculated by the IRS based on how much you owe and when they receive your return and payment. The IRS will bill you for this; it will not be calculated by TurboTax.
Do you need forms for a year earlier than 2016? And.....do you have the income documents you need like your W-2's and 1099's?