Travel document shown by directors in Golf? I don’t know (8,4)
I believe the answer is:
boarding pass
'travel document' is the definition.
(I've seen this before)
'directors in golf? i don't know' is the wordplay.
'directors' becomes 'board' (board of directors).
'golf?' becomes 'g' (phonetic alphabet: alpha, bravo, charlie etc.).
'i don't know' becomes 'pass' (e.g. response in a quiz).
'board'+'in'+'g'+'pass'='BOARDING PASS'
'shown by' acts as a link.
(Other definitions for boarding pass that I've seen before include "travel document" , "prerequisite for high-flyers?" .)