Altered the revised printed paper (10)
I believe the answer is:
letterhead
'printed paper' is the definition.
'letterhead' can be an answer for 'paper' (letterhead is a kind of paper). I'm not sure about the 'printed' bit.
'altered the revised' is the wordplay.
'revised' is an anagram indicator.
'altered'+'the'='alteredthe'
'alteredthe' with letters rearranged gives 'LETTERHEAD'.
Can you help me to learn more?
(Other definitions for letterhead that I've seen before include "Preprinted name, address etc at top of notepaper" , "Where name and address are shown" , "Address, name etc printed at top of notepaper" , "Printed address on stationery" , "Heading on stationery" .)