I did not include second stimulus payment on my return. should I amend my 2020 return ? If I should, How do I do that ?

If you have already filed your return you will need to wait and see if your return gets accepted or rejected. 

• If your return will be rejected by the IRS, then all you have to do is make the changes on your return and refile.
• If your return gets accepted you will have to wait and see if you receive your refund that includes the additional credit. If yes then you will need to amend your return and send the funds back to the IRS. Please see  FAQ How to amend a tax return for instructions.
   
  But the IRS has not addressed the details yet. Please see this IRS Recovery Rebate Credit for more information.

Please see the links below when Form 1040X is available:

• IRS forms availability table for TurboTax individual (personal) tax products
• State forms availability table for TurboTax individual (personal) tax products