This is an example page. It differs from posts because it always stays in the same place and (with most themes) is displayed in the navigation bar. Most people start with an "About Us" page with an introduction for potential visitors to the website. For example, it could say:
Hi, by day I work as a bike courier, by night I'm an aspiring actor and this is my blog. I live in Berlin, have a big dog called Jack, like the Fantastischen Vier and a cold beer.
As a new WordPress user, you should go to the dashboard to delete this page and create a new page with your own content instead. Have fun!