It sounds like you may have accidentally e-filed your state return. Are you in Iowa?
That's what i thought but nope, electronic filing of IA taxes did not happen.
I did e-file Iowa state for the additional fee.
Somewhere it said to fill and sign IA 8453-IND within one day of acceptance.
Then what? So I had the same question, but found the correct answer here, in the form instrutions, apparently not available from State of Iowa.gov
Ref https://www.esmarttax.com/tax-forms/iowa-form-ia-8453-ind-instructions/
See this line: (notes and bold added)
Return the completed form ( IA 8453-IND ) to the ERO ( Electronic Return Originator)
or paid preparer, unless self-prepared. If self-prepared, retain the IA 8453-IND.
That's correct. You don't need to mail Form IA 8453-IND to the Department of Revenue, simply retain it for your records.