The place you will get all formalities done is Wielkopolska Voivodship Office in Poznań – Citizen and Foreigner Department pl. Wolności 17, 61-739 Poznań.
We encourage you to get familiar with information provided by Migration Forum.
Registration of residence
If you are living in Poznań and you want to legalize your stay, you are obliged to register your current place of residence. The registration of residence should be permanent or temporary if you are staying on the territory of Poland more than 3 months.
Detailed information concerning registration of residence can be found here.
PESEL number serves population records. After registering your residence (for at least 3 months) you are given such number automatically within 10 days. More detailed information concerning the number are here.
Registration of residence and PESEL number can be obtained in Town Hall of Poznań – Citizen Department, 16/20 Libelta St.