Hi - 

If you originally filed your return with TurboTax, we can help streamline the steps outlined above. If you used TurboTax Online, simply log in to your account and select “Amend a return that was filed and accepted.” If you used our CD/download product, sign back into your return and select “Amend a filed return.”
https://turbotax.intuit.com/tax-tips/amend-return/how-to-file-an-amended-return-with-the-irs/L6kO691...

Tips
• You must file a separate Form 1040-X for each tax return you are amending.

Heads up
• Amended returns can take more than three months for the IRS to process.

• Line 5a on Form 1040 or 1040-SR is for the total amount of pension and annuity payments you received during the tax year.
• You calculate that figure by adding up the amounts in box 1 of any Forms 1099-R you received from financial service providers.
• Leave line 5a blank if your pension and annuity payments were fully taxable. Enter the total amount of those payments on line 5b instead.
  
  Once you select Amend, you will add the 1099-R and answer the follow-up questions to determine if the amount received is taxable.
  https://ttlc.intuit.com/turbotax-support/en-us/help-article/import-export-data-files/enter-1099-r/L6...