A candidate holding a foreign diploma shall submit:

a) diploma bearing the apostille clause (if the diploma can be recognized as equivalent to a Polish diploma under an  international agreement),
b) certificate confirming that the diploma is recognised as equivalent to a Polish diploma (issued on the basis of recognition of foreign diplomas).

https://nawa.gov.pl/en/recognition/recognition-for-academic-purposes/applying-for-admission-to-doctoral-studies

Documents drawn up in a foreign language (other than English) shall be submitted by the candidate together with their translation into English. Translations of official documents must be certified by a sworn translator.

Kwalifikator allows to automatically generate a general Recognition Statement concerning recognition of a given type of higher education degrees obtained abroad.

Nostrification is an official procedure which is conducted to determine the Polish equivalent of a foreign diploma: https://go-poland.pl/nostrification-higher-education-diplomas