I have a 1099-R from Office of MRO. I am a survivor widow of a retiree from a federal employee. the 1099-R I received. The taxable amount is unknown what is that mean?

TurboTax Online will use the simplified method to determine the taxable portion for box 2a of your CSF 1099-R.   Presume that:

• Monthly payments were received, 
• Payments started in 2025, and 
• That box 7 is code 7.

You will need to know: 

• The amount of the employee contributions (should be in box 9b),
• The date the annuity started,
• The number of months that payments were received in 2025, 
• The age of the recipient when the annuity started,
• The age of other beneficiaries (if there are any), and 
• Was the recipient under the retirement age for the plan.

Follow these steps: 

• Down the left side of the screen, click Federal.
• Down the left side of the screen, click Wages & Income.
• Click on the down arrow to the right of Retirement Plans and Social Security.
• Click to the right of IRA 401(k) Pension Plan Withdrawal (1099-R).
• At the screen Who gave you a 1099-R, select  Office of Personnel Management (CSF 1099-R).
• At the screen Annuity information, select Yes for the question Did you start getting payments in 2025.
• At the screen Annuity information, select No for the question For the years you received these distributions, was the total amount shown in the form the amount you paid tax on?
• At the screen Annuity information, enter the annuity start date, plan cost, months payments were received and amount recovered in previous years.  (This will be $0 if this is the first year that you receive the payment.)
• At the screen Annuity Information, Plan Cost should be in box 9b.
• At the screen Annuity Information, enter the beneficiary ages.
• The taxable amount will be computed by the simplified method.

View Federal 1040 tax return line 5a and 5b at Tax Tools / Tools / View Tax Summary / Preview my 1040.