I dont know how to enter box 12. I can't locate my return from last year and TurboTax doesn't show my last years documents so I could see how I filed last year??

If you used TurboTax Online to complete and file your 2020 tax return, you can access a copy by following the steps in this TurboTax help article: How do I access a prior-year return?

If you used TurboTax CD/Download software to complete and file your return, then TurboTax would not have a copy as your tax return would be stored locally on your computer or storage device. 

You can also request a copy of your tax return from the IRS, however, if you have an immediate need, you can get a copy of your tax transcript from the IRS. See How do I get a copy of my tax return or transcript from the IRS? for more information. 

If you did use TurboTax Online last year and you don't see 2020 tax data, it might be in a different TurboTax account. You can check to see if you may have multiple Intuit accounts by following the steps in the below help article.

How many Intuit accounts do I have with TurboTax?