After sending a payment with a paper 4868 form, register the payment in form 4868 of Turbo Tax and also in Schedule 3 Line 10 "Amount paid with request for extension to file". Additionally, one needs to confirm that line 31 of the 1040/1040SR Worksheet reflects the payment.
Thanks for asking this question because it is hard to find this simple but important task in the Turbo Tax documentation.
