TurboTax 2016 software is no longer supported by Intuit.
You can download forms from the IRS web site at the link below.
https://www.irs.gov/prior-year-forms-and-instructions?find=1040&items_per_page=200
It is way too late to get a refund for a 2016 return---that refund was forfeited a few years ago. But if you owe tax due, you still owe it with late filing penalties and interest. TurboTax software is only available as far back as 2020, so you cannot use TT. You can prepare the return on paper forms or seek local paid tax help.
You might want to go to a local accountant or tax place if you have a complicated return. For simple returns you can fill out the forms by hand.
You can fill out the blank forms for free.
Here are some blank forms & instructions for 2016
1040 https://www.irs.gov/pub/irs-prior/f1040--2016.pdf
Instructions https://www.irs.gov/pub/irs-prior/i1040gi--2016.pdf
1040A https://www.irs.gov/pub/irs-prior/f1040a--2016.pdf
Instructions https://www.irs.gov/pub/irs-prior/i1040a--2016.pdf
1040EZ https://www.irs.gov/pub/irs-prior/f1040ez--2016.pdf
Instructions https://www.irs.gov/pub/irs-prior/i1040ez--2016.pdf
2016 Tax Tables https://www.irs.gov/pub/irs-prior/i1040tt--2016.pdf
Publication 17 Tax Guide for 2016 https://www.irs.gov/pub/irs-prior/p17--2016.pdf
Don’t forget your state. And you will have to print and mail your returns. So be sure to attach copies of your W2s and any 1099s that have withholding on them. You have to mail federal and state in separate envelopes because they go to different places. Get a tracking number from the post office when you mail them for proof of filing.
Important! Mail Federal and State in separate envelopes and mail each year in separate envelopes.