IRS says:
E-filing is available for amending 2019 and 2020 returns that were originally e-filed. E-filing amended returns
will result in much faster processing and refunds. See IRS.gov/Form1040X and IRS.gov/filing/amendedreturn-frequently-asked-questions. Contact your preferred tax software provider to verify their participation in amended return e-filing, for specific instructions needed to submit an amended return, and for answers to any questions.
