First, let me extend my condolences. If your wife passed during the 2016, then you file 2016 as you always have, as married filing joint (assuming that that's what you did before).
However, on the Personal Info page, you will be asked your marital status as of 12/31/2016. Answer "
Widowed". The software will then ask when she passed. Indicate 2016. This will trigger the software to ask information about your spouse, with the date of her passing at the bottom of the information page.
TurboTax will take care of printing "Deceased XX/XX/XXX at the top of page 1 of the return (as required by the IRS) and also the signature.
NOTE: although you indicated "Widowed", for tax purposes you will be filing "Married Filing Joint" for 2016 (I assume that's what you did in previous years). That's OK. In 2017, your tax status will be Single or Qualifying Widow(er), if you have a dependent living with you.
For further information on the death of a spouse, tax, and TurboTax, please see https://turbotax.intuit.com/tax-tools/tax-tips/Family/Death-in-the-Family/INF12090.html
