The form on which your benefits would be reported is a 1099-SSA.  You enter it under Social Security income, just as you would any other 1099-SSA.

Type the words social security benefits in the Find box on the upper right, hit enter, then the Jump To that appears.

To prepare estimated tax payments, go to Federal Taxes, Other Tax Situations, Form w-2 and Estimated Tax Payments.  Estimates are done on your entire tax return, not just one source of income.