If you are a holder of a visa your staying in Poland is fully legal and you are not obliged to register your stay.
If you are a citizen of one of the countries outside the EU and you have residence permit of EU country (excluding Poland) you can visit Poland without a visa, but you cannot stay longer than three months.
For a longer stay in Poland (more than three months) there are two possibillities:
- applying for a visa (in your home country) - recommended
- registration in Urząd do Spraw Cudzoziemców (Office for Foreigners in Poland)
For registration you need to provide us the following documents: (documents prepared in a foreign language shall have a certified translation into Polish attached)
1) evidence that the foreign national has the residence permit, referred to in Article 1(2)(a) of Regulation No 1030/2002 issued by another European Union Member State with the annotation “student;”
2) evidence that the foreign national has health insurance within the meaning of the Act of 27 August 2004 on health care services financed from public funds or a confirmation that the insurer covers costs of treatment on the territory of the Republic of Poland;
3) evidence that the foreign national has sufficient funds to cover the cost of living and return travel to the European Union Member State which issued the residence permit referred to in Article 1(2)(a) of Regulation No 1030/2002 or the long-stay visa, with the annotation “student,” to the foreign national in the amount required for foreigners applying for a temporary residence permit for the purpose of studies https://udsc.gov.pl/en/cudzoziemcy/obywatele-panstw-trzecich/chce-przedluzyc-swoj-pobyt-w-polsce/zezwolenie-na-pobyt-czasowy/studia-i-nauka/studia/
Please find the details in the following website: