Since you have already filed the 2023 tax return, the extension request is no longer relevant. You need to ask this lender why they need the form 4868 for your loan when they already will have access you your 2023 tax return.
You can see if the Form 4868 is included in the PDF of your 2023 online tax return -
To access your prior year online tax returns sign onto the TurboTax website with the User ID you used to create the account - https://myturbotax.intuit.com/
Start the 2024 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 2023 and Click on Download/print return (PDF)