If your spouse died during the tax year, you are still allowed to file with the status "Married Filing Joint".  Next year if you have qualifying dependent children, you may file with the status "Qualifying Widower" (for two years).  After two years and while you still have qualifying dependent children, you are then able to file your returns with the status "Head of Household".  If you do not have qualifying dependent children,  you will then file as "Single".

When completing the Personal Information:  Name, Address, Age, Occupation portion of your return, you must include the information for the deceased spouse.  That information is required to file "Married Filing Joint" after your spouse has passed.