Almost all printing of data that a patron might need from the circulation desk is customizable via Tools > Notices and Slips. This is *not* the case for fines, which are hard coded in koha-tmpl/intranet-tmpl/prog/en/modules/members/printinvoice.tt This is requested occasionally -- if nothing else, it would make Koha more internally consistent.
*** This bug has been marked as a duplicate of bug 10708 ***