Currently, the furthest "edge" of space we can see is about 15 billion lightyears away from the Earth.
That's because we estimated that the universe began in about 15 billion years ago, after the the "big bang".
It means that the the furthest stars, which are located 15 billion lightyears away from the Earth are actually the image of the beginning of the universe.
No one really knows where the universe ends. Because the image of the beginning of the whole Universe might not be appeared yet.
Scientists believe that the Universe is expanding. I think that it might only because more and more "light" of the far star are coming to us after billion and billion years of travel.
Please excuse me for any technical error. I learned those from an article.