Fix a direction indicator (6)
I believe the answer is:
assign
'fix' is the definition.
(I've seen this before)
'a direction indicator' is the wordplay.
'direction' becomes 's' (S is an example).
'indicator' becomes 'sign' (I've seen this before).
'a'+'s'+'sign'='ASSIGN'
(Other definitions for assign that I've seen before include "Appoint or designate to perform task" , "Allocate, a job say" , "Set aside for a specific purpose" , "Transfer or appoint to" , "Give responsibility to" .)