How do I get a signed copy of my tax return for 2020 if I filed using TurboTax? The print return option isn't signed?

Of course it is not signed.   You need to print it yourself, take out a pen and sign it in ink if you need a signed copy for some reason.   When you e-file, there is no physical signature on the tax form.   You "signed" it electronically when you entered your AGI or PIN.  Sign on page 2 next to the words "Sign here."

if someone wants the preparer's signature, this isn't going to happen. You are the preparer.