If you received a Form 1099-R and there is an amount in box 2a of the form then that is taxable income reported on your federal tax return.
To enter, edit or delete a form 1099-R -
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 IRA, 401(k), Pension Plan Withdrawals (1099-R), click the start or update button