tax return filed for 2021 and did not get paid but audited and need to add the stimulus that was not paid out for 1400.00
Yes, you can amend your 2021 tax return. You'll need to paper file. See: How do I amend my federal tax return for a prior year? for guidance to amend, if needed.
Note- you have 3 years from the due date of the original return to file an amended return. That means you must file the amended return no later than 4/15/25.