I didn't file my taxes last year so I bought Turbo Tax 2023 and it's not letting me e-file

No.   Only some professional paid tax preparers using pro software can e-file past year returns.  You cannot e-file a past year return using do-it-yourself TurboTax.  Your 2023 return can only be filed by mail.  Print it, sign and date it in ink, and mail it in.

When you mail a tax return, you need to attach any documents showing tax withheld, such as your W-2’s or any 1099’s.  Use a mailing service that will track it, such as certified mail so you will know the IRS/state received the return.

Federal and state returns must be in separate envelopes and they are mailed to different addresses.  Read the mailing instructions that print with your tax return carefully so you mail them to the right addresses.