This is a sample page. It differs from posts in that it stays in the same place and (in most themes) is shown in the site navigation. Most start with an imprint, the privacy policy or an „About us“ page to introduce themselves to potential visitors of the site. For example, it might say:
Hello! By day I work as a bicycle courier, by night I am an aspiring actor and this is my website. I live in Berlin, have a large dog named Jack, like Piña Coladas, but dislike being left standing in the rain (without an umbrella).
… or something like:
The company XYZ was founded in 1971 and has since supplied the public with high-quality products. At its location in a small city the business employs over 2,000 people and supports local residents in many ways.
As a new WordPress user you should visit your dashboard to delete this page and create new pages and posts for your site. Have fun!