The easiest and quickest way is to use the IRS webpage I'm linking below. You'll be able to access your 2019 transcript (an abbreviated return) which will include your 2019 AGI.
Get Transcript | Internal Revenue Service (irs.gov)
*** I am NOT a tax expert. I am a seasoned TurboTax user, and volunteer to provide assistance to TT users. Nothing I post is to be considered TAX ADVICE; I bear no legal liability for responses.***
