It depends. You cannot do anything to your return once you submit them. You will need to wait to see if your return was rejected or accepted. If it is rejected you are able to login to your return to fix what you missed and refile the return.
If your return is accepted, then you will need to file an amended return. You should not try to amend your return until the original return has been fully processed and you have received your refund or your payment has cleared.
Amended returns do not “catch up” to your original return and replace them; they are processed as two separate returns.
Amended returns have to be printed and filed by mail. It can take the IRS up to 12 weeks or longer to process them. If you are due a larger refund than on your original return, your amended return should only show the difference and you will receive a separate check for it. If you owe money on your amended return, it will show only the new amount owed, you will have to mail a check with the return.
The option to amend a 2021 tax return will become available later in the tax season.
Additionally, all income needs to be reported regardless of the amount so you will have to report the $400 income from the W2.
