Here's Schedule 1. Did you have any of these items? https://www.irs.gov/pub/irs-pdf/f1040s1.pdf
Look at your tax return. Anything on lines 8 or 10?
How to get a copy after filing
https://ttlc.intuit.com/community/prior-year-return/help/how-do-i-get-a-copy-of-a-return-i-filed-thi...
