Go to Federal> Wages & Income>>Retirement Plans and Social Security (SSA1099 and 1099RRB) to enter your SSA1099.
What box? Do you need to enter the SSA-1099?
Enter a SSA-1099, SSA-1099-SM or RRB-1099 under
Federal Taxes on the left side or top
Wages and Income
Then scroll down to Retirement Plans and Social Security
Then the second line - Social Security (SSA-1099. RRB-1099) - click the Start or Revisit button