Marshal can vote for unit in Brazil (7)
I believe the answer is:
centavo
'unit in brazil' is the definition.
'centavo' can be an answer for 'unit' (centavo is a kind of unit). I'm not sure about the 'in brazil' bit.
'marshal can vote' is the wordplay.
'marshal' is an anagram indicator (I've seen 'marshals' mean this (marshal can mean to gather)).
'can'+'vote'='canvote'
'canvote' is an anagram of 'CENTAVO'.
'for' is the link.
Can you help me to learn more?
(Other definitions for centavo that I've seen before include "Mexican coin" , "Small coin of Mexico, Brazil, etc" , "Foreign money" , "(Of games) alternately on one's ground and an opponent's" , "A little money" .)