Admits church has added page in holy book (7)
I believe the answer is:
accepts
'admits' is the definition.
('accept' can be a synonym of 'admit')
'church has added page in holy book' is the wordplay.
'church' becomes 'ce' (abbreviation for Church of England).
'has added' is a charade indicator (letters next to each other).
'page' becomes 'p'.
'in' indicates putting letters inside.
'holy book' becomes 'acts' (book of the Bible).
'ce'+'p'='cep'
'cep' placed into 'acts' is 'ACCEPTS'.
(Other definitions for accepts that I've seen before include "Consents to receive" , "Admits" , "Says yes" , "Takes; approves" , "Takes (an offer)" .)