Work on paper — wrong bit used (7)
I believe the answer is:
subedit
'work on paper' is the definition.
(I've seen this before)
'wrong bit used' is the wordplay.
'wrong' indicates an anagram.
'bit'+'used'='bitused'
'bitused' with letters rearranged gives 'SUBEDIT'.
(Other definitions for subedit that I've seen before include "Work for daily" , "to work on newspaper" , "Check newspaper copy" , "Correct copy" , "daily duty?" .)