If you filed with TurboTax last year, you would be able to log into the same account you used last year to access your AGI. If you did not file with TurboTax, you can request your tax transcript from the IRS - https://www.irs.gov/individuals/get-transcript. (You may want to file an extension if you chose this option.)

If you do not was to request your transcript from the IRS, your only other option would be to print and mail your return.

How do I find last year’s AGI? https://ttlc.intuit.com/replies/3301618