how can you confirm efiled 2020 1040x was properly transmitted and accepted?

[HelenC12]

To check your amended return e-file status, see How do I check my e-file status?

You can track the status of your Federal amended return using the IRS website “Where's My Amended Return” or you can call 1-866-464-2050, (You need to wait about 3 weeks from the date you mailed your amended return for information to show up in their system).

Generally, Form 1040-X,  Amended U.S. Individual Income Tax Return, must be filed within three years of the date the original return was filed, or within two years of the date the tax was paid, whichever is later.

[fanfare]

did you get the message from the IRS ACCEPTED ?

It may take up to 24 hours.