The IRS never "acknowledges" mailed tax returns other then issuing a refund if one is due.
E-filing 2019 has nothing to do with 2018. For e-file purposes your 2018 AGI was 0 because if was filed late and will never be entered into the e-file database.
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**
