To complete the Form 3911:
Write “EIP1”, “EIP2” or "EIP3" on the top of the form to identify which payment you want to trace.
Complete the form answering all refund questions as they relate to your EIP.
When completing item 7 under Section 1: Check the box for “Individual” as the Type of return. ...
Sign the form.
https://www.irs.gov/pub/irs-pdf/f3911.pdf
