Were federal and state taxes withheld, box 4 and box 12?  What is the code shown in box 7?  The taxable amount shown in box 2a is entered on your tax return as ordinary income and taxed at your current tax rate.

No taxes withheld

This second answer does not apply.  As I said in the original question, this is not a pension plan annuity.

All Forms 1099-R are entered the same way in TurboTax.  The taxable amount shown in box 2a is entirely includible in your 2018 AGI.

To enter 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

Or enter 1099-r in the Search box located in the upper right of the program screen.  Click on Jump to 1099-R