Insert account in document folder — easy (6)
I believe the answer is:
'easy' is the definition.
'insert account in document folder' is the wordplay.
I cannot quite understand how this works, but
'account' could be 'ac' (abbreviation for account) and 'ac' is present in the answer.
'document' could be 'file' (a file is a formal document) and 'file' is present in the remaining letters.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for facile that I've seen before include "Easy or superficial" , "Oversimplified" , "Smooth" , "Too easily achieved, glib" , "Easy, simple" .)