Work hard on article and logo (6)
I believe the answer is:
slogan
'logo' is the definition.
(I've seen this before)
'work hard on article and' is the wordplay.
'work' becomes 'slog' (I've seen this before**).
'hard' is an anagram indicator.
'on' is a charade indicator (letters next to each other).
'article' becomes 'a' (indefinite article).
'and' becomes 'n' (common abbreviation for 'and').
'a' after 'n' is 'na'.
'na' anagrammed gives 'an'.
'slog'+'an'='SLOGAN'
(Other definitions for slogan that I've seen before include "short political statement" , "Identifying catchword" , "Catchy phrase in advertisement etc" , "Motto, catchy phrase" , "'Motto, watchword (6)'" .)