If you used TurboTax, you can access your return by logging in using the same TurboTax account that you used to file your 2020 return. Please see How do I access a prior-year return? for instructions.
You can also get your AGI by obtaining an online tax return transcript from the IRS. Please see Can I get a copy of my tax return from the IRS? for more information.
@yellowmagic97-
