is OK to..; is alright to..; may I..?
Says that an action is permitted or acceptable, or asks permission to do something.
This pattern is used to give or ask permission. When you say テレビを見てもいいです, it means "It's OK to watch TV" or "You may watch TV." To ask permission, raise your intonation: テレビを見てもいいですか? means "May I watch TV?" It's a very common, everyday expression, especially in polite conversation.
You can also use it to say something is acceptable in a situation. For example, ここに座ってもいいです means "It's alright to sit here." The pattern is made by taking the て-form of a verb and adding もいいです. For nouns and な-adjectives, use で instead of て: 学生でもいいです (It's OK to be a student), 元気でもいいです (It's fine if you're healthy).