Do you have a child? You can file a Joint return the year your spouse died. For the next two years following a husband's or wife's death, the surviving spouse can file as a qualifying widow or widower if they have a qualifying child. That basically lets you continue to use the same tax brackets that apply to married-filing-jointly returns. After the year of death if you don't have a child you file as Single.
Then to file Single you should start over and set up a new account for yourself and not transfer from last year. You will have to re enter any prior carryovers and depreciation, etc. manually.
See the eligibility rules on page 9 of IRS publication 501
https://www.irs.gov/pub/irs-pdf/p501.pdf
See Turbo Tax help article
https://ttlc.intuit.com/community/using-turbotax/help/how-should-i-file-my-return-if-my-spouse-recen...
