To be invited, apply to the Editor (5)
I believe the answer is:
asked
'to be invited' is the definition.
(I've seen this in another clue)
'apply to the editor' is the wordplay.
'apply' becomes 'ask' (I've seen this in another clue).
'to the editor' becomes 'ed' (abbreviation).
'ask'+'ed'='ASKED'
(Other definitions for asked that I've seen before include "Inquired" , "Enquired; invited" , "Put a question to" , "Demanded" , "Requested" .)