Stick bill on top of present (6)
I believe the answer is:
adhere
'stick' is the definition.
('adhere' can be a synonym of 'stick')
'bill on top of present' is the wordplay.
'bill' becomes 'ad' (advertisement stuck on wall).
'on top of' is a charade indicator (letters next to each other).
'present' becomes 'here' ('here' can be similar in meaning to 'present').
'ad'+'here'='ADHERE'
(Other definitions for adhere that I've seen before include "Stick to - cement" , "Keep" , "Stay attached" , "Bond" , "Stick to as by suction" .)