State papers collected by Ms Poste, say (7)
I believe the answer is:
florida
'state' is the definition.
(Florida is an example)
'papers collected by ms poste say' is the wordplay.
'papers' becomes 'id' (identification papers).
'collected by' indicates putting letters inside.
'ms poste say' becomes 'flora' (Flora Poste, character in Cold Comfort Farm).
'id' placed into 'flora' is 'FLORIDA'.
(Other definitions for florida that I've seen before include "The Sunshine state, capital Tallahassee" , "Miami's state" , "Everglade State" , "Member of union" , "US location" .)