Where do I find Social Security Adm 's TIN?

You don't need one if you are  entering it in the correct place in the program ...

To enter Social Security benefits reported on form SSA-1099

• Click on Federal Taxes (Personal using Home and Business)
• Click on Wages and Income (Personal Income using Home and Business)
• Click on I'll choose what I work on (if shown)
• Scroll down to Retirement Plans and Social Security
• On Social Security (SSA-1099, RRB-1099), click the start or update button

Or enter social security benefits in the Search box located in the upper right of the program screen.  Click on Jump to social security benefits

There is not a TIN on a SSA-1099 received from the Social Security Administration.  You are entering the SS benefits in the wrong section of the program.  Delete the form you are entering.

To enter Social Security benefits reported on form SSA-1099

• Click on Federal Taxes (Personal using Home and Business)
• Click on Wages and Income (Personal Income using Home and Business)
• Click on I'll choose what I work on (if shown)
• Scroll down to Retirement Plans and Social Security
• On Social Security (SSA-1099, RRB-1099), click the start or update button

Or enter ssa-1099 in the Search box located in the upper right of the program screen. Click on Jump to ssa-1099