I got the form 3531 for the year 2020. I realized I did the same thing for this year too. Can I go ahead and send a signed return for this year along with the W2s or should I wait to get a 3531 in the mail for 2021. I'm not sure how this will effect my 1040 X I filed last month for 2021. I figured if I could fix my error before getting a notice would help. Thanks for any insight.