Straightforward form of credit (6)
I believe the answer is:
direct
'straightforward' is the definition.
(I've seen this before)
'form of credit' is the wordplay.
'form of' indicates anagramming the letters (the letters need to be in another 'form').
'credit' anagrammed gives 'DIRECT'.
(Other definitions for direct that I've seen before include "Outspoken" , "Straight, without diversion" , "Instruct" , "Take charge, of company or performance say" , "Take charge, of a film perhaps" .)