You do not enter anything on your tax return to say she is retired, unless you want to use "Retired" as her occupation. Occupation has no effect at all on your refund or tax due.
If she is receiving Social Security or retirement income from a pension plan, retirement account, etc.
Social Security
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.
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.
You can change your wife's occupation to Retired in Personal Info as Tax Champ @xmasbaby0 says.
Most of the changes for retirement will take care of themselves, though you may have to start making estimated tax payments.
Estimated tax payments
You may have to make start making estimated tax payments due to retirement. Up to 85% of your Social Security may become taxable, boosting your total taxable income.
Additionally, you may be withholding too little or nothing at all from pension payments. You can change the amount of withholding by filing a new W-4P.
The IRS levies a penalty for underpayment of estimated tax if you didn’t pay enough tax throughout the year, either through withholding or by making estimated tax payments.
Generally, most taxpayers will avoid this penalty if they owe less than $1,000 in tax after subtracting their withholdings and credits, or if they paid at least 90% of the tax for the current year, or 100% of the tax shown on the return for the prior year, whichever is smaller.
Refer to Penalty for Underpayment of Estimated Tax
Changing your occupation