Very sorry for your loss. For the year that your spouse died, you can still file a joint return. That way, you will get the married filing jointly standard deduction of $25,100 (+ $1350 for each spouse 65 or older) which will lower the amount of income you are taxed on.
In My Info, you will need to indicate that your spouse died. When her name is in My Info, there is a screen early in the interview that asks "Do any of these apply to [name] ?’” where you will do that, and then a drop down will appear where you can enter the date she passed.
If you have dependent children still living at home, you will be able to file as a qualified widower for the next two years after this tax return. Post back if you need further help.
You may file Married Filling Joint. Enter your tax return with all of your data and your spouse's data.
Sign the return on behalf of your spouse, unless your spouse has an executor or personal representative with power of attorney, who will sign for her.
Please accept our condolences for your loss.