If you had a plan purchased from the Marketplace (state or federal) and filed without including form 8962 (which TurboTax generates from your form 1095-A information), then the odds are very high that with a few weeks of the IRS accepting your return, that you will see a letter sent to you from the IRS asking you to complete and return form 8962. So, wait for the letter.
Read the letter carefully as the IRS might not require that you amend your return, but do what the letter says in any case.
NOTE: if for some reason your return is rejected by the IRS for e-filing, then you will have the opportunity to reopen the return in TurboTax, add the 1095-A information, and then e-file as if for the first time. In this case, you won't see a letter from the IRS, so be sure to check your return's status.
Since your return has already been accepted you will need to wait for your return to be processed (refund deposited or letter from the IRS).
In the case of missing 1095A information the IRS normally catches these and will send you a letter with instructions on how to correct. Usually the instructions are to provide a copy of the form 1095A and form 8962 from your tax return.
To get the form 8962 you will sign in to your TurboTax account and select the option to "Add a State".
This will allow you to enter your return and make changes without amending.
You will enter the 1095A information in the "Medical" topic.
Once you complete the updates, you will be able to download your return to your computer.
Then using your print menu you can find and print the form 8962 from the downloaded file to send to the IRS.
Again wait for the IRS notification.