Universe is all the thing outside in what we are. it is like vast and vast and a very vast body which is of indefinite size. it consists of the earth, the solar system, the plants and many more celestial bodies. we are in a very small part of the universe.
moving on to your next question,"how was it created". particularly nobody on earth can probably answer about how was the earth created. some believe it was mainly due to the some scientific things and some believe god created the universe. so, i think that this is an unsolved answer.