If your mother's estate was less than (approximately) $5.4 million, you are not required to file Form 706.
If you are required to file Form 706, it would be a good idea to have a tax attorney or CPA who specialized in estates prepare the form, as it is very complex. This form is not supported by TurboTax, but can be located at https://www.irs.gov/pub/irs-pdf/f706.pdf. Instructions can be found at https://www.irs.gov/pub/irs-pdf/i706.pdf
If the estate was less than $5.4 million, you may be required to file a fiduciary return (Form 1041) to report any income of the estate.
Note: The due date for the fiduciary return may not be April 18. There is an election available to base the tax year of the estate on the date of death (which is made when you apply for an EIN for the estate). For example, if your mother passed away in July, the estate can elect to have a tax year that ends on June 30, 2017, with the return due October 15, 2017.
If you need to file a fiduciary return for the estate, you can use TurboTax Business to do so. The software can be found at https://turbotax.intuit.com/small-business-taxes/
