Apostille is a special mark (stamp) put on official documents issued by institutions of one state for recognition by official institutions in another state. Therefore, only documents issued in Poland can be apostilled in Poland.
Apostille verifies the authenticity of an official’s signature and status, as well as a seal and stamp on an official document. Apostille does not certify the authenticity of the content, though.
Apostille is a simplified legalisation procedure that only applies to the signatories of the 1961 Hague Convention treaty.
Apostilled foreign documents are recognised in all member countries of the Hague Convention and do not require any other form of certification.