Always the same, educational document? (7)
I believe the answer is:
uniform
'always the same' is the definition.
(I've seen this before)
'educational document?' is the wordplay.
'educational' becomes 'uni' (I can't explain this - if you can you should believe this answer much more).
'document?' becomes 'form' (form is a kind of document).
'uni'+'form'='UNIFORM'
(Other definitions for uniform that I've seen before include "Military wear" , "Official clothing" , "a soldier must assume this" , "army's gear" , "Clothing worn by members of a particular group" .)