What do I need to visit my friend in Ukraine.?

I'm a Filipino seaman and my best friend is Ukrainian. He's from Izmail and he's inviting me to come to Ukraine and stay with his family for a while. I also have other friends in other parts of Ukraine. Sevastopol, Odessa and Kherson. I'd like to visit them too. If I will be staying with my friend's house what doents must I prepare. Where in Manila can I go to apply for a visa?