how did you pay? using direct debit or sending payment, there is no receipt. your proof is an entry on a statement from the funding source. If you used a money order, there's nothing. for payments made online using IRS Diret Pay, there should have been an option to print or save the transaction. If you didn't, the proof would be on a statement from the funding source. You can register with ID.ME if needed and access your account transcript
https://sa.www4.irs.gov/sso/?resumePath=%2Fas%2FiSXshuopGb%2Fresume%2Fas%2Fauthorization.ping&allowI...
