I receive a Pension from the United Nations. They do not provide a 1099-R form. How to I declare this income?

You can post the information, and then add a 1099-R

Under Federal

1. Wages & Income
2. Scroll to IRA, 401(k), Pension Plan Withdrawals (1099-R) [Add/Edit]
3. Did you get a 1099-R in 2024? [yes]
4. If you are adding a 1099-R [+ Add another 1099-R]
5. The steps are the same from here
6. [Change how I enter my form]
7. [Type it Myself]
8. If necessary chose a person [Continue]
9. Who gave you a 1099-R? Click box [Continue]
10. Post the 1099-R Information as best you can
11. Be sure to enter box 7 as 7 Normal Distribution [continue]
12. Do you have info in Box 2a or Box 2b? Yes/No
13. Is the IRA/SEP/SIMPLE box on this 1099-R checked? [no]
14. Where is your distribution from? Probably None of the above
15. This should be a Non Qualified Plan
16. Do any of these situations apply to you?
    1. [X] I need to file a substitute 1099-R
17. Post this and complete the interview