Claim everything, for example, at Evans Head (6)
I believe the answer is:
allege
'claim' is the definition.
(to allege something is to make a claim)
'everything for example at evans head' is the wordplay.
'everything' becomes 'all' (all things).
'for example' becomes 'eg' (short for 'exempli gratia', 'for example' in Latin).
'at' means one lot of letters go next to another.
'head' says to take the initial letters.
The initial letter of 'evans' is 'e'.
'all'+'eg'+'e'='ALLEGE'
(Other definitions for allege that I've seen before include "Declare without actual proof" , "hold" , "Declare without being able to prove" , "Assert - maintain" , "Aver (without proof)" .)