Page layout (6)
I believe the answer is:
format
'page layout' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for format that I've seen before include "Secure firmly in position" , "Style or arrangement of a TV programme" , "Arrangement or lay-out, say of book" , "Design, lay-out" , "Prepare (a disk) for data" .)