Can't find my past tax returns. I have emails saying it was filed. Turbo tax won't show me it.

many users have multiple accounts.

see this webpage for ways to find it

https://ttlc.intuit.com/turbotax-support/en-us/help-article/account-management/many-intuit-accounts-turbotax/L9aVfKS1Z_US_en_US 

And if you are in the correct account (assuming you used the "Online" software for 2023 taxes)?

If you didn't use that account for your 2024 taxes, then you still have to start thru the initial series of 2024 questions...before the "Tax Home" selections shows up on the left side menu......and then that will allow you to find the 2023 PDF file to download.  (No...you don't have to actually file 2024 taxes...just start thru some of the questions for it)