You do not document that you retired. But if you have a combination of W-2 income and retirement income, those sorts of incomes are entered in different parts of the software.
Enter your W-2 in Federal>Wages & Income.
If you are receiving Social Security benefits-- Do not try to enter your SSA1099 or RR1099RB as a W-2. Go to Federal> Wages & Income>>Retirement Plans and Social Security (SSA1099 and 1099RRB) to enter your SSA1099.
If you are receiving income from a pension or retirement account--
To enter your retirement income, Go to Federal> Wages and Income>Retirement Plans and Social Security>IRA 401 k) Pension Plan Withdrawals to enter your 1099R.