You have two different questions.
1. If you inherited her IRA, you had the option of cashing it out all at once or over 10 years. If you cashed it out all at once, it is added to your tax return and you pay whatever tax is owed. You get credit for any withholding, but you might owe more, depending on all the facts and circumstances. You don't need to do anything else with your tax return. If you inherited the IRA then this is your income and it goes on your tax return.
2. But then you asked about your mother's tax return. If she died in July 2024, then someone needs to file a 2024 return in her name that reports her income, deductions and credits up to the date she died. (Any income paid after she died is handled differently.). The person who files her final tax return is called her personal representative. This is usually her next of kin, or the executor of her estate. You may need to go to court or file a form with the probate court, it depends on state law. If you are expecting a refund, you need to include form 1310 so it can be paid in your name rather than your mother's name.
There is more information here.
https://www.irs.gov/individuals/file-the-final-income-tax-returns-of-a-deceased-person
https://www.irs.gov/forms-pubs/about-publication-559
https://www.irs.gov/newsroom/how-to-file-a-final-tax-return-for-someone-who-has-passed-away
3. The estate is a separate legal entity that comes into existence after she died. It covers income received after she died (like a final pension payment). For small estates, that income can be handled by you as "income in respect of a decedent" rather than filing a separate estate tax return, which requires a different version of turbotax and extra paperwork.
