You can still fund a Roth IRA, as long as your contribution is sent in before the official tax deadline of July 15, 2020 (the IRS has extended the deadline due to the virus).

You do not need to amend your return.

Please see the response from MargaretL

No, you won't have to necessarily amend and refile your tax return... but you may want to amend to check if you qualify for a retirement saving contribution credit, which may or may not impact your refund. Roth IRA contributions do not reduce you taxable income but may qualify you for the retirement savings contribution credit. So, when you do contribute, just start amendment, enter your contributions and visit the credit (steps below) to see if your refund is impacted... if it is, amend and mail your amended return. If not, there is no need to do anything.

1. Federal Taxes
2. Deductions & Credits
3. Retirement and Investments, select Retirement Savings Contributions Credits

And - if you enter the contribution into TurboTax, the program will help you keep track of your basis to the Roth IRA.  

It seems  retirement savings contribution credit is for low income people, and I don't need to do so.

Thanks.

The only concern then is to be sure the ROTH is marked for the correct year and done by July 15.

Thank you, @KarenJ2.  That is the question I was looking for.  Do you have a link from the IRS website that we can save for future reference in case the IRS says no we should have amended our taxes here?

You do not have to amend the tax return until there is a change in the amount of your 2019 tax liability.  A Roth contribution is not tax deductible so it won't change your liability.  But if the contribution allows you to claim the Saver's Credit, you should amend.   You can prepare the amendment in TurboTax so that TurboTax can track your basis, but you would not need to mail it to the IRS unless there is a change in your tax bill or refund amount after the change.  I suggest you amend and enter the contributions (if you make them before 07/15) for the purposes of tracking your tax basis.  But you will not have to file it (sign and mail it) unless the final numbers change.  

To confirm, here is an IRS tool you can use to determine the answer to ''Should I file an amendment?''.  

@Aladdin1 

Thank you very much, @DawnC.   Would you answer still hold if I am actually putting $6K into a Traditional IRA then converting it to Roth IRA using the backdoor conversion?

According to this link, we (married filing jointly) do not quality for Roth IRA, and our Traditional IRA is not deductible, so we are doing the backdoor conversion after we had filed our tax returns.