I already filed my W-2 this year but I have a 1099-MISC form for the year of 2018 that I didn't file. Is it possible to still file this through Turbo Tax?

[DoninGA]

A 2018 Form 1099-MISC can only be entered on a 2018 tax return.

To complete a 2018 tax return using TurboTax you would need to purchase, download and install on a personal computer one of the 2018 desktop editions from this website - https://turbotax.intuit.com/personal-taxes/past-years-products/

A 2018 tax return can only be printed and mailed, it cannot be e-filed.

OR -

See this TurboTax support FAQ for amending a 2018 tax return originally completed and filed using TurboTax - https://ttlc.intuit.com/community/amending/help/how-do-i-amend-a-return-in-turbotax/01/27579