If you e-filed the Form 4868 extension request using the TurboTax Easy Extension, then you have sign onto the TurboTax online account using the same User ID you created for the account - https://myturbotax.intuit.com/
The Form 4868 will be included in the PDF download.
Start the 2023 online tax return by entering some personal information then click on Tax Home on the left side of the screen.
On the Tax Home webpage -
Scroll down to the section Your tax returns & documents. Click on the Year and Click on Download/print return (PDF)
Or -
Click on Tax Tools on the left side of the online program screen. Then click on Print Center. Then click on Print, save or preview this year's return. Choose the option Include government and TurboTax worksheets