Page put on line, showing official residence (7)
I believe the answer is:
rectory
'official residence' is the definition.
(a rector's house)
'page put on line' is the wordplay.
'page' becomes 'recto' (right-hand page of an open book).
'put on' is a charade indicator (letters next to each other).
'line' becomes 'ry' (abbreviation for railway).
'recto'+'ry'='RECTORY'
'showing' acts as a link.
(Other definitions for rectory that I've seen before include "Incumbent's house" , "Clergyman's house" , "Ecclesiastical dwelling-house" , "Vicarage" , "Clergyman's residence" .)