When selling a property there are a number of documents that will need to be in order, see below a list of the main ones:
Proof of Identity
Property Title Deeds: a copy is kept at notary where you bought it.
Planning Permission or Building Permits: a copy is obtainable from the town hall building department
Cadastral floor plans: a copy obtainable from the land registry office
Town Planning use class Certificate: required for the sale of a plot of land and it is issued by the town hall building department.
Energy Performance Certificate (EPC): an EPC is needed before your market your property and is issued by an accredited assessor.