I filed my 2019 tax return, but realised that I omitted about $40 of account interest. My account has said it'll cost $1000+tax to make the amendment. I'd rather just give IRS the whole $40. Is there anyway to do this?
Do it yourself and mail it in: https://www.irs.gov/pub/irs-pdf/f1040x.pdf
Enclose a check made out to "U.S. Treasury" for the amount on line 20 of form 1040-X, "Amount You Owe."