Ukrainian has different words for you (singular) - ти - and you (plural) - ви. But ви can also be used for formal polite you (singular), in very formal settings it usually is capitalized Ви, e.g. when writing a greeting card to your boss. As I see you learn German, that would correspond to German du, ihr and Sie respectively.
Твій/твоя/твоє is a possessive pronoun formed from the pronoun ти, while ваш/ваша/ваше is formed from the pronoun ви.