The 2019 AGI is on the 1040 line 8b. You can preview the 1040 or print the whole return
https://ttlc.intuit.com/community/accessing/help/how-do-i-preview-my-turbotax-online-return-before-filing/00/26160
How to get a copy after filing
https://ttlc.intuit.com/community/prior-year-return/help/how-do-i-get-a-copy-of-a-return-i-filed-this-year-in-turbotax-online/00/25932
Or do you need your last years 2018 AGI that you filed in 2019 to efile your 2019 return now?
The 2018 AGI is on 1040 line 7. It will be on the first page.
How to find the AGI
https://ttlc.intuit.com/community/agi/help/how-do-i-find-last-year-s-agi/00/25947