When filing an income tax return for someone who is deceased, please enter "in the estate of the late" for the individual on the income tax return itself. You do not have to enter it on the envelope.
TurboTax provides instructions for entering this within the software, but when I attempted to do so I received a message that the first name and last name were not in the proper format. This needs to be fixed in the software, or the help file needs to be rewritten for next year's edition. I ended up writing it on the printed return itself (which has to be mailed in anyway).