If this came from an IRA or retirement plan then they will send you a 1099-R form in January to enter into the program ... wait for it and all the other tax documents before you file as required by law.
Enter a 1099-R here:
Federal Taxes,
Wages & Income
(I'll choose what I work on - if that screen comes up)
Retirement Plans & Social Security,
IRA, 401(k), Pension Plan Withdrawals (1099-R).
OR Use the "Tools" menu (if online version left side) and then "Search Topics" for "1099-R" which will take you to the same place.
Be sure to choose which spouse the 1099-R is for if this is a joint tax return.
Be sure to pick the correct 1099-R type: Standard 1099-R, CSA-1099-R, CSF-1099-R, RRB-1099-R.
If you were the beneficiary of the plan, the plan custodian will send you a 1099R form by February 15. After that, just follow the instructions in TurboTax for a 1099-R. With most such plans, because your mother did not pay income tax on the contributions, you will owe income tax on the amount withdrawn or paid out.
in the unusual situation that your mother had named no beneficiaries for her retirement plan, the retirement income would have been paid to her estate, and you will need to file an estate tax return.