Since your return is accepted you would need to amend your return to make corrections. The amended form in TurboTax will not be available until sometime in mid-February. Amended returns must be mailed.
You should wait before you amend, the IRS most likely will send you a letter regarding the missing form. If they don't and your return gets fully processed, you would then amend.
How do I Amend (Change or Correct) a 2016 Return with TurboTax?
https://ttlc.intuit.com/replies/5114064
