I started filing my 2020 taxes with turbo tax now I can't find it?

I'll assume you are asking about a 2020 return you worked on last year.  Currently Online TurboTax is only for 2021 returns.

If you started a 2020 return last year and didn't finish it, your account should still have the 2020 PDF and the *.tax2020 data file (if you're in the same account.)     I'll tell you how to normally get it.  If you don't find it in your Online account, I've also provided info below about how to look for multiple accounts.  

NOTE:   If you already paid for your 2020 Online return last year, TurboTax Support should furnish you the 2020 desktop software so you can finish it.   It cannot be efiled; it has to be printed, signed, dated, and mailed.

First see this:

FAQ:  How do I access my prior year return?

https://ttlc.intuit.com/community/prior-year-return/help/how-do-i-access-my-prior-year-return/01/270...

Log in and go to the Tax Home.  Scroll down the Tax Home page to the section "Your Tax Returns & Documents."  Expand that section and choose the tax year 2020.   Then you can choose to "Download/print the PDF" or download the 2020 tax data file (which requires 2020 software to open).

If you do all that, but there's no evidence of prior returns in that section "Your Tax Returns & Documents", then you likely have multiple accounts and signed into the wrong one.    Many people end up with multiple accounts without realizing it.

You can have up to 5 accounts that use the same email address for notification purposes.  A User ID may be an email address, but it doesn't have to be.  It might be only part of an email address, or it can be anything at all.

To get a list of your User IDs, reset password, and recover account access, etc., you can use the tool at the link below.  When using the Account Recovery tool, try using your phone number first if you can still access it.   After that, if necessary, then run the tool on your email address(es) you can access.

NOTE: Before running the account recovery tool below, log out of all Intuit accounts including this user forum, or you might end up in a loop.  Then clear your browser Internet cache, close your browser, then reopen it, and go to the link below.  You may wish to copy this link so you can paste it into the new browser session.

https://myturbotax.intuit.com/account-recovery

If still no luck after running that on your phone number you can still access and email address(es) that you can access,  here's another method:

Go back to the tool again, but this time leave the data field blank, scroll down a bit, then choose the small blue link that says "Try something else", and it will look you up by SSN and other parameters.