You don't furnish proof when you file your return.
You just enter the 1099R as you got it and if the IRS asks for proof - and only if they ask, then you provide proof.
To enter pension and annuity Payments (1099-R)
• Click on Federal Taxes
• Click on Wages and Income
• Click on I'll choose what I work on (if shown)
• Scroll down to Retirement Plans and Social Security
• On IRA, 401(k), Pension Plan Withdrawals (1099-R), click the start or update button
