If you e-filed and your account says “pending” you cannot add/change anything. If you did not enter 2018’s AGI it will be rejected when the IRS starts to accept/reject on Jan 27 and then you can add it before you re-file.
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
