Itemizer

2 clues
Schedule A completer
Taxpayer using a long form, usually
Similar answers:
Actionitem
Actionitems
Adlitem
Anitem
Antagonizer
Appetizer
Appetizerorder
Appetizers
Athomasizer
Atomizer
Atomizers
Authorizer
Baptizer
Bigticketitem
Bitemark
Bitemarks
Biteme
Bitemontana
Caesarseizer
Closetorganizer