You can amend your return to add this information but do not amend yet.

First you will need to wait and see if your return is Accepted or Rejected by the IRS. If the return is Rejected you can go back in and fix the mistake without amending. If the return is Accepted you will need to WAIT until you receive your refund and then Amend.

Follow these steps to amend: ( Amend forms will be ready mid February 2017)

https://ttlc.intuit.com/replies/3288565

You cannot change or add anything on the return that you just e-filed.  It is too late, just like when you put an envelope in a US mailbox

Now you have to wait until the IRS either rejects or accepts your return.  If your return is rejected, you will be able to go into your account and make the necessary changes to your tax return and re-submit your return. 

 If the IRS accepts your return, however, then you have to wait longer until it has been fully processed and you have received your refund.  THEN you can prepare an amended tax return and mail it in. You will need to use a form called a 1040X. You cannot e-file an amended return.  They have to be mailed, and it takes at least 2-3 months for the IRS to process an amended return.  Meanwhile, DO NOT go in and start changing anything on your return in the system, or you will make a mess for yourself.  Sit tight and wait until you see what the IRS does with the return you just e-filed