A Tax Registry Number (AFM)
This tax number (AFM) is mandatory for all buyers, including foreigners and permanent residents abroad.
It is issued on the spot at tax offices, free of charge. All applicants must present their passport.

A Greek Bank account
All necessary payments will be made through this account, also you can use this account to pay automatic your bills when you are not in Greece (electricity water and phone bills.) Opening a bank account in Greece only takes a few minutes and requires no minimum opening deposit. All you need is your id or passport and your afm number.   
                                               
A Residence Permit 
A resident’s permit called the blue card is required. You must apply for this in person at the local police station, Issuance takes approximately 2 weeks. This permit is just a formality for EU nationals, (You will need to have your EHIC card with you, 6 passport photos and a Greek bank account)

A notary Public
A notary public is a government-appointed lawyer who processes and certifies all real estate transactions, including drawing up and reviewing all official documents to ensure the legal transfer of the property.
 
Lawyer / solicitor
Solicitors carry out necessary legal surveys and conduct a property title check. They ensure the property is free of any mortgage notes, claims, expropriations, rights-of-way and, in general, any legal encumbrances.