'I entered the date of filer's death on TurboTax but the Form 1040 does not have \"Deceased, name, date of death\" on top of the return.'

Go back and recheck your answers in MY INFO. It depends where you entered the information. As you go through MY INFO and reach the screen that asks does any of these apply to XXX, di you nter the information here?

Also, if you are looking at the forms preview, the name may not appear at the top of the 1040 initially. If you haven't paid for the Online program, once you pay, you may go to the print center and preview the forms that will be sent to the IRS. Then the 1040 should say Deceased, name of the deceased, and date of death.  I have included a screenshot what this looks like like. Note this is not a real tax return or a real person.