How do I complete my 2023 return using my TurboTax account after successfully filing for an extension?

[Fred-2019Taxes]

How do I complete my filing extension?

[xmasbaby0]

You just prepare and file normally.   The IRS knows you have an extension.   You need to make sure that the estimated payment you made when you requested your extension is entered:

When you requested your extension you were supposed to pay your estimated tax due.  Did you enter the payment you made into your tax return?  Go to Federal>Deductions and Credits>Estimates and Other Taxes Paid>Other Income Taxes 

You have until October 15, 2024 to use online TurboTax and to e-file.  After that, online TT and e-filing will close down, and you will have to use the CD/download and file by mail.