Do not try to change anything on your return now. When you amend, your Form 1040X has to be prepared from the return exactly the way it looked when you filed it originally. You have to wait. Once your return has been processed you will complete a Form 1040X --- which is not yet available --- and submit it to amend the mistakes made when you filed your original return. It takes the IRS at least four months to process an amended return.
The 2020 Form 1040X does not become available until the end of March 2021 (subject to change).
https://www.irs.gov/forms-pubs/new-information-for-form-1040-x-filers
The 1040X will not be available in the software until March 26. You are correct that the the paper form is on the IRS site. You can print out that 1040X form if you want to use it—-and prepare your amended return by hand to mail in instead of waiting to use the software and e-file it.
**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.**
